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The MasterPage Article I Thought I’d Never Finish

Wednesday, April 12, 2006

… because it kept growing and growing. I was determined to finish this off tonight before falling asleep (always dangerous).

Master Pages: Tips, Tricks, and Traps is an article covering all the inconspicuous points of developing and designing with master pages. Everything from URL rebasing, the munging of client side identifiers, using FindControl, nesting, and even tips for cross page posting.

As always, I appreciate any feedback. I’m particularly interested to know if the reader finds the intermingling of Visual Basic and C# samples to be useful, or just a terrible idea.

Now to sleep, perchance to dream...

Peter Kellner Wednesday, April 12, 2006
Great Article! I never realized there was so many things to worry about on a Master Page
Jun Meng Wednesday, April 12, 2006
Great article! :)

One typo (maybe): "We can visualize what the object hierarchies would look like at runtime with the following diagram." Here you mean "at design time", right?
scott Wednesday, April 12, 2006
Jun: that first diagram would be what the objects look like at the very start of the page lifecycle, before Pre_Init and before the master page injects itself. I'll try to edit the article later tonight and make that a bit more clear.
steve Friday, April 14, 2006
Outstanding! Thanks.
Eric Golpe <egolpeATgmail.com> Tuesday, April 18, 2006
Hi Scott,

Question.. I have a base class in App_Code that extends the UI.Page class, and so I created a .master page, and on the content page, I changed BOTH the Inherits attribute of the aspx to the new extended base class name, AND the class declaration (class Default3 : MyExtendedPageClass) but I get:

"Make sure that the class defined in this code file matches the 'inherits' attribute, and that it extends the correct base class (e.g. Page or UserControl"

Should I NOT change the class declaration?

and one more while I got you interested... Can you use multiple user controls programatically on a Master page itself? (not the content page) and what is the correct way to do it??

I hope you can help me out. Thanks!! GREAT article BTW
scott Tuesday, April 18, 2006

Make sure you also add the CodeFileBaseClass attribute in your @ Page directive and point it to that base class.

Yes, you can programatically use user controls on a master page. I wouldn't treat the master page any different than a regular Page, all of the same examples apply.
Jon Tuesday, April 18, 2006
Hi Scott,

Good Article. I've been fumbling with findcontrol and masterpage's for a while. I decided to use the property get set instead, much cleaner. I'm curious though and forgive me if I missed this or if this is a stupid question but is there a way to expose all of the controls properties as opposed to just the specific property, when you call it?


Chris Tuesday, April 18, 2006
> left at the other Scotts blog. LEft here for the sake of being in the right place. :-)

I completely and thourgh;y hate the Name Mangling when using master pages. It makes it damn near impossible... or highly impractical to create sanely named CSS outside of using themes.

This becomes twice as bad when you have developers who do the code, and designers who do the CSS, and you have a predefined Id naming conventions. The Id the designers see in the .aspx source isn't what you get in the output, obviously makeing CSS mistmatch the expectations.

It's why we're not using master pages at all.
scott Wednesday, April 19, 2006

I can't think of an easy way to expose all of the controls as properties (without writing all the code, that is). Perhaps some sort of macro or VS add-in could do that by generating code.


I understand your problem. I guess it is a trade-off the ASP.NET team made (easier for postback resolution, harder for css and javascript). Perhaps it's something they could provide a workaround for in the future.
scottgu@microsoft.com Wednesday, April 19, 2006
Chris -- I posted a reply to your comment on my blog post: weblogs.asp.net/.../443276.aspx#FeedBack

Hope this helps,

Ryan Anderson Wednesday, April 19, 2006
Some one give this guy another medal.
Nice, thorough, well thought out.
One of the things I appreciate about your tech writing style is that you just don't say, "this is how you do it..."
You give different examples of how it can be accomplished, and then revisit each scenario and point out the pros and cons of each and expanding on the best direction to go. That style is nothing short of value added!
Many thanks for your continued efforts in contributing to edumacation of us knuckleheads out here! :)
Jon Wednesday, April 19, 2006
Thanks Scott,

Well even if I can't define the entire control it's still a better solution then working with findcontrol. I was pleased to find out I could issue a Atlas UpdatePanel Update command within the property get set routine to show the new changes, since a have a update panel in my master page. It works like a charm. I agree with Ryan about your tech writting style. Keep up the good work!!!
Nisar Khan Friday, April 21, 2006
Hi Scott,
I have read your great article and i have question for you :) if you can please help me.,
i try to implement you code esp "Master Page To Content Page Interaction"

i have setup as you have described in your web site and i always get "null" value here:

i'm working VS2005:

protected void SendEmailButton_Click(object sender, System.EventArgs e)
SendEmailEventArgs eventArgs = new SendEmailEventArgs(this.EmailAddressBox.Text);

if (SendEmail != null) <<always null value
SendEmail(this, eventArgs);

if you want to see the whole page, please let me know and ii can post here or email you whichever is easy for you., hope to hear from you soon.

Nisar Khan Friday, April 21, 2006
do you have anything related with:

Content Page To Master Page Interaction?

thank you
Scott Allen Friday, April 21, 2006
Yes, the article covers interaction in both directions.
Scott Allen Friday, April 21, 2006

The event will be null until someone subscribes to the event. Typically the page would subscribe to the event (SendEmail += new SendEmailEventHandler(...))
Brian Friday, April 21, 2006
Regarding FindControl,

I find it's behavior so annoying I created a simple routine to find any control within any other control. This uses recursion to return the FIRST control matching the supplied name. If the control is not found it simply returns null, instead of raising an exception. Let me know what you think.

public static Control Find(Control C, String ControlName)
if (C.ID == ControlName) return C;

foreach (Control c in C.Controls)
Control cntrl = Find(c, ControlName);
if (cntrl != null) return cntrl;

return null;
steve Sunday, April 23, 2006
The last part of your article, "Nesting Master Pages" and "Content controls are allowed only in content page that references a master page" issue, the fix for that really saved me

Atul Reddy Tuesday, April 25, 2006
Only after reading your article, i realized that there are many work around ways in dealing with 'MasterPage's.

Quick Question-
Any idea on how to create 'Menu round shaped multiline Tabs'in webforms (Asp.net 2.0) similar to 'Tabcontrol' now available in winforms (.net 2.0).
Any available references?

My Email- atulreddy@yahoo.com
Vani Tuesday, April 25, 2006
Please let me know how to add server controls/web custom controls/user controls to a master page. In vs 2003 version, we had something like the Tag Prefix - how do I call that tag name and prefix after Registering the tag with name a nd other attributes n vs2005 ?

Ed Tuesday, April 25, 2006
Great article and so helpful. Thanks. I am getting a NullReferenceException: when I try and set the footer text from the content page. Base Class is BaseMaster,
BaseMaster footer = new BaseMaster();
footer.FooterText = "My Footer"; in the contentpage in Page_PreInit, or page load or in a LinkButton1_Click, bombs.
Any idea what I am missing?

I can access and set other properties in the Base Class, no prob but the setting I lifted from your article that starts with
“protected Label FooterLabel;” fails. Thanks again for a great article I will be working on it for a while.

scott Thursday, April 27, 2006
Ed: You shouldn't have to "new BaseMaster()" if that is the base class for your master page. It's an inheritance relationship.
Diego Beltran Friday, April 28, 2006
Hi Scott,

Your article is very impressive. I have a question though. My case is as follows:
I use a master page which has 4 main ContentPlaceHolders (header, footer, subNavigagion and Main content)

The content pages (child pages of this Master Page) will, at Page_PreRender event load different user controls into this place holders, based on a selected language (up to 7 different languages) and reading from a global resource file (items.resx, items.fr.resx, etc.).

What happens is that the user controls, such as dropdowns or checkboxes, buttons etc… trigger the autoPostBack event but do not go into the actual Click event. For instance: a dropdown will look like this inside the UserControl:
Protected Sub lstAttributeName_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstAttributeName.SelectedIndexChanged

End Sub

But at runtime, it goes into the pageLoad event for that UserControl and it NEVER reaches SelectedIndexChanged method.

HOW can I make this dropdown to actually go into this method? I’ve been spinning my wheels on this for a while now.

Please help me if you can.

Much appreciated.

Diego Beltrán
trevork Friday, April 28, 2006
A well constructed, useful article - thanks!

You asked for comments about mixing VB and C#?
I have to say, I found it annoying.

Tyler Carver Tuesday, May 2, 2006
Hi, awesome article. I have a question about dynamically setting the MasterPageFile on the parent of a nested MasterPage. I can't seem to find a way to do this dynamically. There is no PreInit event for the MasterPage and the Page that is loading has to set the nested page as it's MasterPageFile. It seems there is no way to get to the MasterPageFile property of the parent master page before the OnInit event is called.

Any suggestions? This would be awesome because I could dynamically swap out the MasterPage including the parent of all nested MasterPages.

James Spibey Tuesday, May 2, 2006
Hi Scott,

Great article - thanks for taking the time to wrote it. I have a particular problem which I don't seem to be able to solve so I was hoping you could offer some insight.

I have a common baseclass called TemplatePage which I use for all my pages which is derived from System.Web.UI.Page. Each page in my site in turn derives from TemplatePage. How can I reference my MasterPage from the TemplatePage class? I get an error at present which states that the master page doesn't exist. I assume that this is because my base class is in the App_Code directory and so the MasterPage class isn't available.

Any advice would be very appreciated
TristanK Tuesday, May 2, 2006
Thanks so much for a staggeringly informative article.

I tried to read it all in one go, but my brain popped, almost as if I'd been struck.

I vow to return, and bring my friends, rough it up a bit, and send it on its way with no lunch money.
Scott Tuesday, May 2, 2006
Tyler: In the PreInit event handler for the Page you could use Master.MasterPageFile = "...";

James: You've identified the problem. Because App_Code compiles before any .aspx and .master files the base page class won't see any master page types. You could define a base class for your master page, too, and the base page class could talk to the master through that base class (an interface also works).
scott Tuesday, May 2, 2006
Thanks, Tristan.
James Spibey Tuesday, May 2, 2006
Thanks for the reply Scott. I added a base class to my Master Page and that got me over this hurdle but I've found another one in that our TemplatePage base class uses typeof to figure out which page we are on and performs certain actions based on that. This doesn't work of course in this new website model so we're stuffed again.

We've decided instead to use Web Application Projects instead because of these problems. Thanks again for your help
Dan O Tuesday, May 2, 2006
Great article - one of the best asp.net articles I have seen.
Tyler Carver Wednesday, May 3, 2006
Scott, thanks for the fast reply. I had been trying to set the MasterPageFile on the nested MasterPage that very way, Master.MasterPageFile =... I now realize that I had created another problem that caused this to fail. It actually does work but I was doing this in my base class to get easy access to the MasterPage in a type safe way:

protected new MyMaster Master
get { return (MyMaster)Master; }

This had been working great but fails in the nested scenario. I can set the MasterType in the page file but I liked doing this in one spot in the base class for all pages. By the way this caused a nasty stack overflow.
Kevin Thursday, May 4, 2006
Good Article. One thing the master pages doesnt give you is the framestyle layout. there is no way to control postback on different sections of the masterpages and I thik that's their downside.
Priya Thursday, May 4, 2006
Good one. I have a custom control with a button. The button click event fires if the page is without master. But, after the master is added, the event does not fire. Can you please help with this? Thanks a lot.

matt vaughn Thursday, May 4, 2006
"You hit one out of the park." I'm currently refactoring a base page that is really overloaded with everything from Session, Authentication, control manipulation, and navigation...

Your discussion of using HttpModules to hook into events from an ASP.Net page was very thorough and well organized. I'm a repeat customer to your blog. Keep up the good work.
scott Friday, May 5, 2006
Thanks, Matt.

Pryia: I'd have to see some code. If you could email me a sample that demonstrates the problem, that would work best.
Priya Raj Friday, May 5, 2006
Scott, I emailed you the code details.

Vik Monday, May 8, 2006
Gr8 article!!! I was just trying to figure out a better way of including JS scripts in content pages, your article helped me in figuring that out & understanding the limitations of master pages.


Avi Tuesday, May 16, 2006
Hi Scott,

I have been racking my brains out on this for days...

I have added a menu control to a master page. The only issue I have is when you click on menu items which have navigateURL assigned (as in site maps) the page changes to the URL specified, and you can not tell which menu item was clicked.

I had no problem with this when I used LinkButtons for navigation (on every page) since I could always access them from various pages and change their color.

Of course, I only care about this behavior at the static menu level only. I am using a dynamic menu based upon the contents of a SQL SiteMap table.

Any help or suggestions would surely be well appreciated.


P.S. Why do I see no examples of anyone trying to manipulate the menu control on a master page?
J.P. Thursday, May 18, 2006

I am having *major* difficulties using the FindControl to access a Button WebControl. I'm using nested master pages, so I've got the following objects I'm working with:

phMain - the ContentPlaceHolderID on my main Master Page, titled ABSOLUTE_main.master
phAdminContent - the ContentPlaceHolderID on my nested Master Page, titled ABSOLUTE_admin.master
btnAdjust - the Button WebControl that resides on my content page

The issue centers around my nested master pages. I did as you mentioned by calling everything out in a single line of code; I used the following (in C#):

WebControl button = (WebControl)Page.Master.FindControl( "phMain" ).FindControl("phAdminContent").FindControl("btnAdjust");

This throws an unhandled NullPointerException, which is on the button "btnAdjust". The button *does* exist, as this line of code (using the hairy munging naming convention) will, in fact, find my button:

WebControl button = (WebControl)Page.FindControl("ctl00$ctl00$phMain$phAdminContent$btnAdjust");

That works...as ugly as it is, but I cannot work this way. I've got other controls that I need to "Find" on the Page, and this guessing game of what the control will ultimately be named is both maddening and impossible.

I decided to simplify my code for grins (try the ol' outward-in trick) by simply seeing what would return from this statement:

ContentPlaceHolder content = (ContentPlaceHolder)Page.Master.FindControl( "phMain" );

Guess what I get??? A null value! Why would I receive a null value on that line of code??? My expectation was to receive an object that I could dissect and eventually work my way into. A null value isn't acceptable.

I decided to go the other way, thinking that maybe the nested master page resolves first, as you suggest in the article. I did the following, by itself:

ContentPlaceHolder content = (ContentPlaceHolder)Page.Master.FindControl( "phAdminContent" );

Any guesses what value came back?? A null. I'm at a serious loss here. What can possibly be going wrong? I can send you anything you need...I'll send it. :)

HELP! :)

I am in an extremely dire situation here. I cannot continue with my project until I get this worked through. Why did I ever attempt to use Master Pages????

Thank you for the article (it was very informative) but it didn't spend enough time on the perils of nested pages. Or, maybe it did, and I just need to stay away from master pages entirely. :)

scott Thursday, May 18, 2006
Avi: I have not worked with the menu control extensively, sorry.

J.P: That does seem like odd behavior. If you want to send me a sample that compiles and demonstrates the problem and I can probably take a look: scott @ OdeToCode.com.
J.P. Friday, May 19, 2006

After contemplating hara-kari (j/k), I continued to poke and prod at this problem. I thought back to something you said ("the page will resolve from the inside out"). My nested page (ABSOLUTE_admin.master) would resolve itself and dump all of its constituent controls into its contentplaceholder, then the main master page (ABSOLUTE_main.master) would resolve, and all of the controls from the nested master page would be dumped into the outer-most master page. THEN, the outer-most master page would dump all of ITS controls into the content page....and away I go.

After thinking about this a bit, I wondered what would return if I tried the following code:

Object obj = Page.Master;

Lo and behold, it was a reference to my nested master page (ABSOLUTE_admin.master). This made sense to me, based on what you said about the resolution timing of all elements.

O.k., so I thought a bit....what happens here:

Object obj = Page.Master.MASTER;

And, as expected, I got a reference to the outer-most master page (ABSOLUTE_main.master).

O.k., so now, with all fingers and toes crossed, I tried the following code and prayed and prayed:

WebControl button = (WebControl)Page.Master.MASTER.FindControl( "phMain" ).FindControl("phAdminContent").FindControl("btnAdjust");

And it worked!!! I think the main thing I have to keep in mind when working with nested master pages is that you ALWAYS have to move to the outer-most level...get a reference to the outer-most ContentPlaceHolder first, then drill into it to get what you need. So, in my case, I needed the master OF THE MASTER to begin my search.

And, it makes total sense...you need to start with the FindControl() method at the page level, then drill into each container to get what you are after. I just need to keep in mind that the ContentPlaceHolders in the Master Page environment are the outer-most containers...always. :)

<insert huge sigh of relief> I sincerely thank you for writing this article, articulating the pitfalls of Master Pages. My Professional ASP.NET 2.0 book from WROX is very well-written, but only introduces you to Master Pages. I was able to get my pages working, but the issues I've been facing have been long and difficult. I believe your article will come in handy down the road to side-step these landmines.

Thanks so much!

Munir Syed Wednesday, May 24, 2006
Hi, Great article and actually very self explantory so well done. It gives me some ideas regarding implementing a framework page. I am looking for more innovative ideas about handling and display page level errors and hooking up masterpage to show business errors using maybe a javascript window(restrictions apply when ie has blocker on!!). Do you have any suggestions about these. I'd be very interested in them. Thanks again, carry on your superb work!
Steve Friday, June 2, 2006
Scott -

Great article, and timely too. I will be back. In the article, you mention using a HttpModule to set the Theme for all pages. Couldn't the same be done in the global.asax in the PreRequestHandlerExecute event? This would save having to configure the web.config for the application. Thoughts?

scott Friday, June 2, 2006

That's true, it's just I've seen global.asax file grow out of control with little bits of functionality here and there, so proceed with caution :)
Gene Saturday, June 3, 2006
Thank you for your work on this article; it helped me a great deal.
Adam Tibi Monday, June 5, 2006
Nice article that should be read before any attempt to use a MasterPage.
Consider this code:
MasterPage 1:
<asp:ContentPlaceHolder ID="cphHead" runat="server">
Some Html...
<asp:ContentPlaceHolder ID="cphBody1" runat="server">

MasterPage 2:
<asp:ContentPlaceHolder ID="cphHead" runat="server">
Some Html...
<asp:ContentPlaceHolder ID="cphBody2" runat="server">

<asp:Content ID="Content1" ContentPlaceHolderID="cphHead" runat="Server">

<asp:Content ID="Content2" ContentPlaceHolderID="cphBody1" runat="Server">

<asp:Content ID="Content3" ContentPlaceHolderID="cphBody2" runat="Server">

This will issue an error saying that the content is pointing to a cph that doesn't exist (which is a logical error). However, I'm building multibranded sites that will need such an approach!

I tried to find ways to catch the error and ignore it, also, tried, in a HttpModule, to find the Content that doesn't have an equivillent CPH to remove it from the page but that didn't work!

The problem is that you can't catch the Content because it doesn't really exist!

Do you have any solution or an alternative approach (not by using IF ELSE) for this problem?

Peter Bromberg Tuesday, June 6, 2006
Best "Get under the hood" Master-Mechanic article on MasterPages on the net. Good work.
Appreciate it!
Rich Monday, June 12, 2006
Great article. Masterpages are what I've been needing ever since I migrated to .net 1.1

Your guide touches on sharing masterpages across multiple apps. Your first suggestion seems the most appropriate although I cannot get it to work. Just a "Masters/Master1.master" file does not exist error. I created the virtual directory for the web app using the masterpage app through the IIS admin. Is that what you meant?

dokmanc Tuesday, June 13, 2006
I must admit your article was a bit over my head, I will try a couple more times to reread it.

In the meantime, I would be most grateful if you could answer a question that I posted to a newsgroup by did not receive a satisfactory answer:

Andy Lee Friday, June 16, 2006
Good work, one thing you didn't mention regarding the relative urls is when you use them within Javascript files.

The only solution i could think of was to pass the server rootpath into a javascript variable and then use this in the javascript file...

<script language=JavaScript>
var rootPath = '<%= ResolveClientUrl(".") %>' + '/';

I added this to the MasterPage.
John Gillespie Sunday, June 18, 2006
A great article as everyone says.

I have a question for you. I have a master page which takes care of tracking page views etc. I then have a content page which varies based on the query string.
I want to have the code in the master called but cache the page content as neccessary.

I can cache the content of the page in a user control and that is fine. What I can't (yet) do is somehow cache the html header section (ie meta tags for keywords, description, and page title), without caching the WHOLE page.

Right now the first request has the updated header but all subsequent (cached) pages revert to the master page's version of the header.
Do you have any idea how I could fix this?


Fabiano Arruda Wednesday, June 28, 2006
very very very great, i've need this tips these days.

thank you very much

Fabiano Arruda
Sukki Wednesday, June 28, 2006
Hi Steve,
i am having one master page and 3 content pages are there.In the content page1 i am giving refernce in the aspx page of remaing 2 pages.Its working fine but "The issue is since each page is compiled to a different assembly it does not know the referes and hence cannot reference it." what the next step i had to proceed?
plz clarify ASAP.

Markus Thursday, June 29, 2006
I wish I had read this before putting months of effort into the site I'm building...
Great article, now I actually understand at least a little bit of masterpages!
Eric Thursday, June 29, 2006

Meta tags is the only trouble we've had with Master pages, which was an oversight on Microsoft's part. Anyway, I tried to implement as you've outlined in the article, to no avail. Here are my steps:

1) Create a new Class file in App_Code that inherits from Page (I've called this MetaPage)
2) That class contains your code and seems to compile OK
3) I then changed an individual ASPX codebehind page to inherit from that new MetaPage instead of the usual Page; this seems to match what you have as well since it's in the @Page directive

Anyway, once I add in the "MetaKeywords" in the Page directive, it barfs that it's not an attribute of System.Web.UI.Page, even though I'm inheriting from my MetaPage instead. I did not touch the Master file, as your example also did not seem to touch the Master file. Any guidance is appreciated. :-)
scott Thursday, June 29, 2006

That is the Visual Studio validation being overly zealous.

The project should still compile and run, it's only Visual Studio that complains because it doesn't know about the property.

Let me know,
Eric Friday, June 30, 2006

No, it neither compiled nor ran. Does the .master also have to inherit from the MetaPage class or just the Page class?

Do you have a working sample project that implements this perchance? I have an alternate solution that doesn't do page directives instead using a Page_Load that calls the Master, but my graphics designers don't do/understand code-behind code, but could deal with page directive codes. They are the ones frequently tagging these, so your solution is the most elegant... if it would work.

Thanks! :-)
scott Monday, July 3, 2006

ARe you using code-beside files (CodeFile="")? If so, use a CodeFileBaseClass attribute also. The CodeFileBaseClass attribute will contain the name of your base class. I'll be posting a sample tonight or tommorow, stay tuned.
doWhileSomething Thursday, July 6, 2006
The article was very informative and although it was not exactly what I was looking for - I figured I would post the question.

I need to find out what page has been loaded as a child of the master page.

Reason, I have a few menus that are on the master page which are in panel containers and I only wish to make certain panels visible depending on which pages are selected.

So, I need to check from the master page what child page is active.

Thanks in advance.
scott Thursday, July 6, 2006
I'd probably have my web forms derive from an interface or base class that can tell the master page what it needs to know.
sbyard Monday, July 10, 2006
To re-inforce what's been mentioned above. There are TWO issues with inclucing Javascript files that contain urls - e.g. you use window.showModalDialog to open an ASPX web page as a dialog.

1 js file location itself has to be resolved in sub-folders
2 url of dialog called in a javascript function requirs resolution

(2) can be resolved as follows in code-behind.
if (!Page.ClientScript.IsStartupScriptRegistered("JavascriptSiteNamePrefix"))
Page.ClientScript.RegisterStartupScript(typeof(Page), "JavascriptSiteNamePrefix", @"<script language='javascript'> var rootPath = '" + Request.ApplicationPath + "/'; </script>");
JetBrain Monday, July 17, 2006
Thanks for the article.. but I have a question... I want to make a dynamic menu in the master page.. I mean that the menu change according to the content of the pages in the place holder.. do you have any idea how can that be done?

Thanks in advance
Zaheer Ahmad Monday, July 24, 2006
I am new to ASP.NET. I don't have much experience. This artical helps me a great. Especially the "Handling the PreInit Event" and "Abstract Interaction" parts are great.
arun Friday, July 28, 2006
i like this artical because it explain how to fine the controls in the master pages and other important features of the mastser pages
Peter Kellner Saturday, July 29, 2006
Hi Scott,

Great article. Two quesitons.

1. any thoughts on how to get a background image into a div tag on a master page? (that works from aspx pages in subdirectories).

2. How to you format your code on your blog?

Thanks! -Peter
scott Sunday, July 30, 2006
Hi Peter:

1) I'd set the background image using CSS and keep the image and style sheet in the theme directory.

2) I use Jeff Atwood's code formatting macro: www.codinghorror.com/blog/archives/000319.html
Peter Kellner Sunday, July 30, 2006
Hi Scott,

I'm not quite understanding what you mean by placing the image in the theme directory. I put the jpg in my directory called "MyProject/App_Themes/ThemeNormal" and made my background in the css this:

<div id="header_image" style="background: transparent url(bg_header.jpg) repeat-x scroll 0% 0%;cursor: pointer;">

I'm still not getting the image.

Sorry for being a little thick.

scott Monday, July 31, 2006
Not a problem, Pete. Does the following work for you?

A web form with a div like:

<div class="myDiv">

and the web form sets Theme="SomeTheme" in the @ Page directive. Inside of the SomeTheme directory is a .css file with the following:

background-image: url('example.jpg');

The .jpg file is also inside the themes directory.

This does work for me as the browser will request the .jpg file relative to where it fetches the style sheet from, so even with web forms in different sub directories the path is valid.

Let me know if that works / makes sense. Getting a little fuzzy here late at night.

Merritt Thursday, August 3, 2006
Best article I've come across concerning Master pages. The section entitled "Headers, Scripts, and Meta Tags, Too" was extremely helpful to me.
James Hebben Friday, August 4, 2006
Fantastic article. It has helped me understand how master pages really work.

I have blogged a tidy solution to including javascript files in a consistent manner.

Arne Bolstad Tuesday, August 8, 2006

thanks for a great article! When implementing the HttpModule i found that my login page crashed. This page is a stand alone page and does not belong to any MasterPage. I resolved it by doing a null check:

Page page = sender as Page;
if ((page != null) && (page.Master != null))

Just thought I should share this...

/Arne (Sweden)
Antoine Monday, August 14, 2006
Great article,

Thanks, it helped.

One note: in Javascript opened windows, the way to address controls on the opener also changes; I didn't figured it out yet though.
Ricky Tuesday, August 22, 2006
Hi Scott,

Great article!

I have some problems though with my master page.
The master page has a backgroung image and a login.aspx as the startup content page. When i ran the project, the image is not displayed in the startup page (login.aspx) but when login is successful and control is transferred to my default.aspx the image is displayed.
In my web.config the authentication mode="forms". Whenever i change this to "windows" the project works fine. How can i display images in the master page when the "authentication=forms" in web.config ?

Hope you can help me.


Scott Hungarter Tuesday, August 22, 2006
I was searching for a very specific problem when i came across this article... specifically trying to use FindControl() within a MasterPage'd site. Awesome article! I found my answer and got a whole lot more too.
Thanks a million!
scott Wednesday, August 23, 2006
@Scott: Thank you for the compliment.

@Ricky: Check this post by ScottGu: weblogs.asp.net/.../437027.aspx
Michael Shapiro Thursday, August 24, 2006

Great article! The best one on this topic.

I have a question that was not covered in it though. In one of the content pages I have the following (simplified) setup - runat="server" omitted, etc.:

<asp:Content ContentPlaceHolderID="driver">
<asp:TextBox ID="tb">

<asp:Content ContentPlaceHolderID="data">
<asp:GridView DataSourceID="ds" />
<asp:ObjectDataSource ...>
<asp:ControlParameter ControlID='<%= GetControlID("data", "tb") %>' .../>

The problem is that GetControlID method is never called in this scenario and request is failing. Obviously, the ControlID parameter for the ControlParameter control is set before...

I've been banging on this problem for quite some time and couldn't find a solution. Any help would be greatly appreciated. It would be also very interesting to hear your recommendations regarding inter-contentPlaceholder controls interactions.

Thanks again for the superb article!
scott Saturday, August 26, 2006
Michael: I don't believe you can use expressions that way. What I'd do is set the property programatically in PageLoad (ControlID = tb.ID).
frank Monday, August 28, 2006

I am using a custom control dervied from compositecontrol class. I have a button in this control which fires an event. When I use this custom control in a normal aspx page it works fine, but in master page the event is not getting fired. Could you help?
Mario Monday, August 28, 2006
I'm trying to use the A Page Directive Approach but I get this error after creating the BasePage class and trying to make one of my pages inherit from it.

Error 1 Error parsing attribute 'metakeywords': Type 'System.Web.UI.Page' does not have a public property named 'metakeywords'. c:\inetpub\wwwroot\showMachines2.aspx 1

What can I do to fix this ??

Roland Monday, August 28, 2006
Thanks for the hard work you put into the article.

We put all this time into figuring out how to use something that is supposed to save us time. You have to ask yourself: was it worth it? Perhaps another excellent article called "Master Pages: Use them? or Avoid them?", would be in order to address the type of site it is worth using them on.
Ricardo Monday, September 4, 2006
Scott, amazing article :) How the flow will works with few ContentPlaceHolders at the some MasterPage ?
ED Friday, September 8, 2006
Great suggestions on sharing the master page. However, how do I get the virtual directory to be visible as I'm developing in my IDE?
Dalia Thursday, September 14, 2006
This is a great article, thanks.
Dot Net New Bee Thursday, September 14, 2006
Great information on Master/Content pages. Thanks.
I am trying to use the "Define a custom SendEmail event, and let each page subscribe to the event" but having problems to get it to work.

Is it possible to display the entire sample here for downloads?

I have the following code in my Content's page but keep getting this error message "No overload for 'EmailReport' matches delegate 'System.EventHandler'" . Can you please tell me what I am doing wrong? Thanks a lot!
protected void Page_Init(object sender, System.EventArgs e)
Master.SendEmail += new System.EventHandler(this.EmailReport);

protected void EmailReport(object sender, classLibrary.SendEmailEventArgs e)
string address = e.ToAddress;
// do work
Patrick Sunday, September 17, 2006

Meta tags is the only trouble we've had with Master pages. Anyway, I tried to implement as you've outlined in the article, to no avail. Here are my steps:

1) Create a new Class file in App_Code that inherits from Page (I've called this BasePage)
2) That class contains your code and seems to compile OK
3) I then changed the Default.aspx codebehind page to inherit from that new BasePage instead of the usual Page; this seems to match what you have as well since it's in the @Page directive.

Anyway, once I add in the "MetaKeywords" in the Page directive, it barfs that it's not an attribute of System.Web.UI.Page, even though I'm inheriting from my BasePage instead. I did not touch the Master file, as your example also did not seem to touch the Master file.

I tried the CodeFileBaseClass attribute as well but that gave me even more errors.

Any guidance is appreciated. :-)
Bill Sunday, September 24, 2006
This was a great article, but I am really bothered by something and was hoping you could clear this up for me. Basically, if you are using master pages, it would appear you cannot even use the basic Autopostback capabilities of, say, the dropdown listbox in a content page and show the selected element with an HTTP Request. Is this true?

I've been testing and it would appear so. This means that currently written applications that you plan on 'wiring up' to a Master Page can no longer use server-based forms that get even simple postbacks (i.e. Request["dropdownlist1"];).

In my testing, I did something this simple and it works without master pages, but once connected (and setting the MasterType virtual path), the code no longer retrieves the data.

Heather Tuesday, September 26, 2006
I have a situation where I have created a master page and then a content page and then on that page I have put a webtab control and then on each individual tab I have put one web user control.

So now I would like to push a button on the web user control that is on the first tab and have the second tab appear or become active.

I need a way to access the webtab control from the web user control that is on the first tab.

This may not be a master page problem at all and if not, I appologize. Thank you.
Richard Wilde Friday, October 6, 2006
Great article on master pages. We use masterpages in .net 2.0 and also use dreamweaver templates. This is so our customers use macromedia contribute to edit pages. This works great however the customer has the ability to change the title tag within contribute. we have a content control within ht e head to set the title tag. However asp.net always adds an empty title tag on the page as well so we end up with 2 title tags.

Is it possible to turn off the title in the page directive or remove it when the page is rendered?

scott Saturday, October 7, 2006
@ Richard: I don't think there is a way to turn of Title in the @ Page directive after the page starts executing. It would have to be something that happens before the page compiles.

@ Heather: That is not really a master page problem, but I'd look at having the control raise an event to the page, and the page will then change the visibility on the tabs.

@ Bill: You have to be careful with using syntax like Request.Form["xyz"], because names can change. It would be better to access the drop down list through the field.

@ Patrick: I'd need to see some code. I believe you sent me an example in email :)
Ram Thursday, October 19, 2006

Very informative article and thanks for that.

I have a question on Sharing the master page with multiple applications.

As you explained in your article, we are implementing with IIS sharing approach. With that approach, I am getting two types of errors

1.When we use MasterType in the aspx page, it added public get property in the corresponding designer file which is by design. But it did not recognize the masterpage type and so the build is failing. Of course the reason was, the application dll can not find the masterpage type. One way to solve this copy the master page project dll into this application bin directory. But whenever we make changes to Masterpages, we need to copy the dll back to application bin direcotry which is big maintenance issue in our case. Did you go through this?

2.Application content page could not find the masterpagefile and so source mode of the page is complaining as "masterpage file not found" Do you think it is VS 2005 issue?

scott Thursday, October 19, 2006

In some cases I skip the strongly typed MasterPage property. Instead, I define an interface in a class library and reference the class lib from both the master page project and the web site project.

The master page can inherit from the interface and implement its members. The content pages cast the MasterPage property to this interface type and invoke the properties.
Danielle Friday, October 20, 2006
Thanks for such a wonderful article. I've been referring to it for awhile to help me programmatically set and reference members of three different master pages I use. The three master pages have quite a bit of overlap, and I decided today I could sandwich those three between a static top and base master so that I could have my base master page always doing the work to figure out the correct master page rather than writing that logic over and over in each .aspx page. SOOO, I have the "Content controls are allowed only in content page that references a master page" problem on my base master that programmatically sets one of three I immediately came here, and sure enough you had a fix...except the MasterPageFile="" trick doesn't seem to work in the @Master directive. Do you have any more tricks up your sleeve?
Tom Clancy Wednesday, October 25, 2006
Why would meta tags in a <head> with runat=server escape the contents inside of them? I have a block in a master page that looks like this:

<head runat="server">
<meta name="author" content="<%= MASTER_COMPANY_NAME %>" />
<meta name="copyright" content="<%= MASTER_COMPANY_NAME %> - <%= CurrentYear %>" />

When a page renders, they look like

<meta name="author" content="&lt;%= MASTER_COMPANY_NAME %>" />
<meta name="copyright" content="&lt;%= MASTER_COMPANY_NAME %> - &lt;%= CurrentYear %>" />
sree Friday, October 27, 2006

After i read your article i created a master page implemengting the following interface:

public interface IMasterForm
string MasterFieldText

after implementing the above interface in masterpage:

public partial class MyMaster : System.Web.UI.MasterPage, IMasterForm
protected void Page_Load(object sender, EventArgs e)
if (ContentPlaceHolder1.TemplateControl.Page.PreviousPage != null)
IMasterForm form = ContentPlaceHolder1.TemplateControl.Page.PreviousPage.Master as IMasterForm;
if (form != null)
if (!string.IsNullOrEmpty(form.MasterFieldText))
//here i will set the label which is supposed to be in all the pages
setLabel = form.MasterFieldText;

public string setLabel
lblResult.Text = value;
return lblResult.Text;

#region IMasterForm Members

public string MasterFieldText
get { return setLabel; }



I want to set the master page values only once in page1 and maintain the same master page values for the remaining pages(page2,page3,page4...)


public partial class Page1: System.Web.UI.Page
protected void Page_Load(object sender, EventArgs e)

protected void Button1_Click(object sender, EventArgs e)
((MyMaster)Page.Master).setLabel = txtBox.Text;


<%@ Page Language="C#" MasterPageFile="~/MyMaster.master" AutoEventWireup="true" CodeFile="Page1.aspx.cs" Inherits="Page1" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<asp:Label runat=server ID=myLableResult Text="TestTransfer1 Page"></asp:Label>
<asp:Button ID="Button1" runat="server" Text="Button" PostBackUrl="~/Page2.aspx" />


After i implemented this logic i could able to browse through into different pages with postbackurl setting in each page control to a different page.

Is this a good idea or is there any other way to implement? as i don't want to implement the interface in each child web form and carry the values along with the child web pages.
scott Sunday, October 29, 2006
@ Danielle:

Not sure I follow the question. ScottGu expanded on the nested master tricks here: weblogs.asp.net/.../430382.aspx.

@ Tom: I would probably add those tags using code behind.

@ Sree: I would probably let the master page maintain its state in the database, or in Session. This keeps the content page and master page a bit more seperated.

Amritha Friday, November 3, 2006

I am developing an application using ASP.NET.

I have a form and would like to include a form within it.

Any help will be appreciated.
David Austin Tuesday, November 7, 2006
Thanks for the article. Amazing!
I find myself very frustrated by the difficulties in using javascript libraries with master pages. I don't really understand the methods posted above for javascript inclusion, so I tried one of the methods you suggested, with no success I'm afraid.
I have a questions.aspx page and a questions.js library in the root directory of my web app. The master page is in a master directory ie:
I can't get VS 2005 to debug javascript written into the aspx page so I have been using included js files for the debugging as well as the efficiency of grouping functionality.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

I think this should work, but it doesn't....

Dim si As HtmlGenericControl = New HtmlGenericControl()
si.TagName = "script"
si.Attributes("runat") = "server"
si.Attributes.Add("type", "text/javascript")
si.Attributes.Add("src", "~/Questions.js")

Any ideas or suggestions would be great.
thanks for your time
Mystifier0505 Tuesday, November 7, 2006

Master Pages cannot access Session?

Saravana Kumar Monday, December 4, 2006
I have page onherited from nested master page.
The base master page has 2 user control and i conent placeholder. my problem is the button click event is not getting fired in the page. It's not at all doing post back.
Graham Monday, December 4, 2006
I'm just starting to use master pages and have put all my navigation buttons there. I'm trying to reset them using the following code structure but can't find any buttons. I tried getting hold of the contentplaceholder, but can't loop through it.
protected void Reset_Buttons()
foreach(Control ctrl in Page.Master.Controls)
if(ctrl is Button)
Button btn = (Button)ctrl;

Scott Allen Monday, December 4, 2006
@David: The "~" character won't work in your example. You'll need to explicitly wrap the URL in a call to Page.ResolveClientUrl to have ASP.NET evaluate the correct path to your .js file.

@Saravana: That is a scenario that should work find. I can't say more without seeing the code.

@Graham: MessageBox won't work on the server. It pops up a windows message box that nobody would be able to see.

Also, the buttons are probably inside a form control. Set trace="true" in your @ Page directive and see what the button's parent control is. Loop through the parent control's Controls collection. Hope that makes sense.
Keren Tuesday, December 12, 2006
Hi scott
great article, I find it very useful, 10X.
I have request can someone please translate the following VB code to C#

<%@ Master Language="VB" %>

<script runat="server">

Public Event SendEmail As SendEmailEventHandler

Protected Sub SendEmailButton_Click(ByVal sender As Object, _
ByVal e As System.EventArgs)

Dim eventArgs As New SendEmailEventArgs(EmailAddressBox.Text)
RaiseEvent SendEmail(Me, eventArgs)

End Sub


<script runat="server">

Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs)
AddHandler Master.SendEmail, AddressOf EmailReport
End Sub

Protected Sub EmailReport(ByVal sender As Object, ByVal e As SendEmailEventArgs)

Dim address As String = e.ToAddress

' do work

End Sub


I cannot understand what are the orders:
RaiseEvent SendEmail(Me, eventArgs)
AddHandler Master.SendEmail, AddressOf EmailReport
what are the parallel functions in C# that I have to wirte down?

and again 10X
Akhilesh Thursday, January 11, 2007
Thank you very much for such a nice article. I wish I should have read it before submitting my project. But any how I have got a great help I was stuck for running a javascript function and I finally found that I should use ctl00_ContentPlaceHolder1_Label1 in place of label1 in content page. Can you please tell what should be used for master Page Controls?????
Saud Friday, January 12, 2007
That was the best article i ever read on Master pages. I am using your tips to write an article which covers Master Pages and Factory Pattern. That was mind Blowing.
Bohemian Friday, January 12, 2007
I have searched high and low and you are the only one whom even comes close to this topic and I am wondering if you can shed some light on it…
“Dynamic Server Controls, Events in content pages that also utilize a MasterPage…”
Basically, for this test I have some dynamic server controls, a dropdown, button and textbox for example…
They are all created in the page_init of the content page as are the event handlers…
Pretty standard stuff, when there is no MasterPage the events are raised as anticipated, when a plain jane MasterPage is added, the dynamic events for said dynamic server controls are not raised…
Can’t seem to make it fly…
Can you shed any light on the subject, possibly a blog article with a functional sample?
Thanks in advance.
Adam Wednesday, January 17, 2007
Thanks for a great Article!
I was wondering if someone would help me with an issue that's driving me insane.

I have a menu control that works fine on an aspx page. However, when I move the control to a Master page, it behaves differently.

Specifically, the when you hover over a link in the Menu control, the entire <td> background should change color. When the control is on the Master page, only the background around the actual text changes.

As far as I can tell, the only difference in the resulting HTML is in the class attribute.

class="Header1_Menu1_1 TopNavLink Header1_Menu1_3" (when it's on the page)

class="ctl00_Header1_Menu1_1 TopNavLink ctl00_Header1_Menu1_3" (when it's on the Master page)

Anyone know why? My designer won't let this slide by!
Michael Holm Andersen Thursday, January 18, 2007
Hi Scott

Great article!

I’m developing a CMS like application, where I would like to use a MasterPage for the “outer design” and a single Content page, which dynamic builds the “inner content” for the page, loading UserControls and “injecting” these into the Content Page.

What I have is this:

.aspx file

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="mhaDynContent.aspx.cs" Inherits="mhaDynContent" Title="Untitled Page" %>

.aspx.cs file

protected void Page_PreInit(object sender, EventArgs e)
this.AppRelativeVirtualPath = "~/mhaDefault.aspx";
this.MasterPageFile = "~/MasterPage.master";
base.AddContentTemplate("ContentPlaceHolder1", new TestContent());

public class TestContent : System.Web.UI.ITemplate

void System.Web.UI.ITemplate.InstantiateIn(Control container)

container.Controls.Add(new LiteralControl("Hello World"));
//Control toAdd = LoadControl("mhaCalendar.ascx");
//UserControl a = new UserControl();

I can easily add a new control (like e.g. the LiteralControl to the “container”, but what I really would like to do is load (“inject”) a UserControl into the container and I can’t make this work (I’ve commented out some of my code – attempts :)

I hope you understand my problem and any help would be appreciated.

Best regards,

Michael Holm Andersen
Kevin Sunday, January 21, 2007
I am having problems getting the master page inheritance to work with the code-beside model. When I follow the example, I can get the visual inheritance to work, but it forces me to put any code "inline" in the master page rather than in a code-beside file.

Does anyone know how I would take this example below and change it to inherit from the base master page class defined below?
File: default.master
<%@ Master Language="C#" AutoEventWireup="true" CodeFile="default.master.cs" Inherits="Resources_default" %>
File: default.master.cs
using System.Collections;
public partial class Resources_default : System.Web.UI.MasterPage
protected void Page_Load(object sender, EventArgs e)
if (!Page.IsPostBack)
Trace.Warn("MADE IT");
File: BaseMasterPage.cs (located in App_Code)
using System;
public abstract class BaseMasterPage : MasterPage
I cannot figure out how to "wire" it up so that my events in the default.master.cs are handled.

I appreciate any suggestions.

Bilge Monday, January 22, 2007
This is an awesome article. I do not have time to read all of it now, but what I did read was invaluable research and insight. I have bookmarked it for later reference. Thanks.
TraceyM Monday, January 22, 2007
Good information, thanks. Anyway to take this a step deeper? I trying to programmatically set the Navigation.Url property of a hyperlink web control inside a ItemTemplate in the form view web control that sits on a content page that has a master page. I'm trying to set this in detail.aspx.vb, I haven't had much luck.

Any assistance would be great...

Master Page: MasterPage.master
Content Page: detail.aspx
Form View Control: FVDetail
HyperLink Control: mapLink
Shoaib Tuesday, January 23, 2007
I have a menu on my master page. When the sub menu opens, it is displayed behind the content in the content placeholder at the center of the page.

I have tried many ways but couldnt solve the problem. I will be thankful if somebody can solve my problem
AustinDeveloper Thursday, January 25, 2007
I just wanted to leave a quick note to say "thanks" for writing this article. I was looking for a good way to allow content pages to override (or augment) the stylesheets included in the master page. This article answered that question (and several I hadn't yet thought of) extremely well. Great work!
Gravatar Kirill Friday, October 9, 2009
Thanks! Best article about master pages I've ever seen.
Gravatar Fidel Saturday, October 17, 2009
Look interesting, but, what i want load a Dynamic Menu based in the User Profile, and the data is in a database, how i make a reference in the "MainMenu" ID control? in the page.aspx.vb y recive a message MainMenu not defined. Can you help me with the solution to reference a Object in the CodeBehind? Thank you for your support.
Gravatar arsema Tuesday, October 20, 2009
Hello every one please help me I am beginner to develop asp.net please help me if you are interested. I try to develop my own sight asp.net with C# ,please help me the upload code and download code asp.net with C# code
Mukesh Monday, October 26, 2009
Thanks for the article. It's very useful.
Bhavana Friday, November 20, 2009
Great article. Thanks Scott!
Sri Tuesday, November 24, 2009
You saved my day! There is stuff in here I did not find elsewhere (topic: "Break URLS..."). Thank you so much!
Gravatar atul Friday, January 1, 2010
Thanks buddy it was great help.
I was wondering to call an event from master page. your article helped me out.
Gravatar Navjot Singh Wednesday, January 6, 2010
"Realy You Give A Good And Very Important Information about master Pages .. Thanks..."
Gravatar Satish Kacham Tuesday, February 2, 2010
Thanks Scott,
You are doing great job.

Satish Kacham
Gravatar Dinil Wednesday, February 24, 2010
Great work man....
Gravatar Luis Fernando Forero Thursday, March 11, 2010
Great article I have a question
I want to change a label in my master page. Thanks to your article I have manage to do that.
The problem is that I have to do that in every page, is there a way to optimize that?
Gravatar Sheila Tuesday, March 16, 2010
Thanks for the article!

I am still having a little trouble. I built a Master page, build a separate Header control, added the control to the master page.

Now on other pages, I would like to access and change the label on the Header control.

Is there a way to do this?

Gravatar Angel Wednesday, March 17, 2010
nice article.

I want to disable back button effect of browser in my asp.net application.but i want to do it in a particular content page of a master page.

can you please suggest a solution.?
Gravatar Kamran Pervaiz Thursday, March 18, 2010
hi K.Scott i m new in web development i m having a great problem here plz help me.
i have a registration flow like 7 to 8 pages....patient inputs data and when it clicks on next updatedataholder() method calls which saves the content of that page and put it in session.
now the complex part i want to implement a breadcrumb thing in master page and i should be able to navigate from 1st to for example 5th page.
Questions is how will i know that what was previous page? and previous page updatedataholder() should be called? the worst approach is i call this method on every page unload event? what do you say?
Thank u in advance.
Gravatar Renato Person Friday, March 19, 2010
Awesome article! Congratulations!
Gravatar Nebyoolae Friday, April 2, 2010
Excellent article. I didn't think I needed the HTTP Module part to make this work, but as soon as I added it, all was well, so thanks!
Gravatar Njoku Samuel Saturday, April 10, 2010
When i try to import images file designed from fireworks . When i place it directly in my master page temp. it makes my app. low to load, because of the images are not sliced.
Gravatar lokesh Wednesday, May 5, 2010
I have an issue with masterpages and default pages

i have master page name :sitemaster.master
control on master :treeview

on form load of Default2.aspx i am changing the label1.text of masterpage.But when i used to go to default3.aspx using tree view then the label1.text of master page is showing empty.
how i can show same text of label1 in default3.aspx also.
If cak give some ideas it will be great help.

thanks and regards,
Gravatar Juan Fco Ochoa Thursday, May 13, 2010
Hi men, GREAT article.

I just want to give you some feedback on the section that you called Name Mangling.

You mention in this section taht for being able to get back information from a javascript block to use it in some field it was necessary to do the next:

Dim script As String = "[Label1ID].innerHTML = 'boo!';"
Dim scriptKey As String = "SayBoo"
Dim addScriptTags As Boolean = True

Protected Sub Page_Load(ByVal sender As Object, _
ByVal e As EventArgs)

script = script.Replace("[Label1ID]", Label1.ClientID)

ClientScript.RegisterStartupScript( _
Me.GetType(), scriptKey, script, addScriptTags _

End Sub
Unfortunlly when you are behind an Ajax UpdatePanel this do not work.

I found some way to fix this issue.

You have to set the next code:

document.getElementById(myFieldID).innerHTML = 'Something'

NOTE: myFiledID is send it from the codebihinf of the asp.net page of this way:

javascriptfucntion('" & txtNombreCliente.ClientID & "')

And this is it. I hope ths be usefull for the people that use to read your article.


Juan Fco Ochoa

Gravatar Juan Fco Ochoa Thursday, May 13, 2010
Hi men, GREAT article.

I just want to give you some feedback on the section that you called Name Mangling.

You mention in this section taht for being able to get back information from a javascript block to use it in some field it was necessary to do the next:

Dim script As String = "[Label1ID].innerHTML = 'boo!';"
Dim scriptKey As String = "SayBoo"
Dim addScriptTags As Boolean = True

Protected Sub Page_Load(ByVal sender As Object, _
ByVal e As EventArgs)

script = script.Replace("[Label1ID]", Label1.ClientID)

ClientScript.RegisterStartupScript( _
Me.GetType(), scriptKey, script, addScriptTags _

End Sub
Unfortunlly when you are behind an Ajax UpdatePanel this do not work.

I found some way to fix this issue.

You have to set the next code:

document.getElementById(myFieldID).innerHTML = 'Something'

NOTE: myFiledID is send it from the codebihinf of the asp.net page of this way:

javascriptfucntion('" & txtNombreCliente.ClientID & "')

And this is it. I hope ths be usefull for the people that use to read your article.


Juan Fco Ochoa

Gravatar pulkit goel Saturday, May 22, 2010
sir i have two content placeholder in my mastetpage. I n my child page in one content placeholder i have grid and in another i have panel containing controls.
So i want that at runtime grid should be visible on whole page and on selecting grid column panel should be visible. But currently at page load my grid is visble on half page and half remain vacant.

so please can u help me i will be very thankful to u
Gravatar Peter Friday, June 4, 2010
Thanks for your outstanding explanation on this issue!
Gravatar Steve Stacel Monday, June 21, 2010

Great article about master pages. I did as you instructed. I added a MasterPageModule class, BasePage class, updated the Webconfig the MyMasterPageModule in httpModules.

When I compiled the code I received the following errorss in my BasePAge Class
Error 1 'BasePage' does not contain a definition for 'PreInit' and no extension method 'PreInit' accepting a first argument of type 'BasePage' could be found (are you missing a using directive or an assembly reference?) C:\Users\sstacel\Documents\Visual Studio 2008\WebSites\WAP_Web4\App_Code\BasePage.cs 20 14 C:\...\WAP_Web4\

Error 2 The name 'MasterPageFile' does not exist in the current context C:\Users\sstacel\Documents\Visual Studio 2008\WebSites\WAP_Web4\App_Code\BasePage.cs 25 9 C:\...\WAP_Web4\

I am not sure what I did wrong. Can you help me resolve it.

Gravatar SHAHRAM Saturday, July 3, 2010
Gravatar Ajay Khatri Sunday, August 8, 2010
Great article...!!! :)

You are really superb ....

Gravatar Razak Monday, August 9, 2010
Thanks a lot for the Find() method that searches for controls. It is exactly what I've been looking for. Good job!
Gravatar Deepa Saturday, October 16, 2010
You have given nice information. I am trying to use controls of the content page in the Javascript of the master page. I am not sure is there any way like to use it directly like ctl000_contentplaceholder_contentctlname which didnt work for me. But my problem is in my master page I don't have BODY tag because it is in content pages and Index page. So in Codebehind of Master page I am getting value of the control of the content page and can assign in the Hiddenfield. But then i can not use that field in the javascript of the master page.
Any help will be appreciated.
Vadim Tuesday, November 9, 2010
Thanks very match for this article!
Al Wednesday, December 15, 2010
Great article! Solved a lot of headaches for me, and possibly prevented a lot of future ones :)
Vinu Friday, January 14, 2011
Nice article...I am a newbie in this field and i need your help ASAP :

I have some dropdown lists (company,region,country etc..)which are used in different web forms. I have a master page too..Now i wanna create a reusable web control for all dropdowns (which should be part of the presentation layer).

And i tried like this- i created one ascx file with a dropdownlist which binds all regions[Region name] from database. And i added ddlRegion.Items.Insert(0,"--Select--"); in Databind().In a new aspx file with a button the control it works fine.ie.When nothing is selected (--Select--) it will alert as 'Select a Region',and if data is selected it will return the correct selectedValue. Now, my problem is that the javascript alert is not working when i use the control with the aspx page where i have used master page reference[i wrote it in ascx page].Or how can get the first item ie.--Select-- from ascx to aspx???

Just help me out from this...
Am using visual studio 2010-C#,sql server 2008
Gravatar scott Friday, January 14, 2011
What does the JavaScript code you wrote look like? Chances are it
isn't finding the right control ID when used in a master page - the
master page changes the control IDs on the client.
Vinu Saturday, January 15, 2011
Thanx for ur fast reply.....Can u give me a brief idea about how to use that with an example?

My aspx page look like this:
<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Company.aspx.cs" Inherits="Basicdata_Company" %>

<%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="cc1" %>
<%@ Register TagPrefix="Dropdown" TagName="Region" Src="~/Usercontrol/Dropdown.ascx"%>
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<script type="text/javascript">
function validate() {
var objname = document.getElementById("<%=txtCompanyname.ClientID %>")
if (objname.value == "") {
alert("Value is required");
return false;

var objurl = document.getElementById("<%=txtUrl.ClientID %>")
if (objurl.value == "") {
alert("Value is required");
return false;
/// I tried this type code for ddlRegion[user control] but it returns error ////

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<Dropdown:Region ID="ddlRegion" runat="server" Width="128px"
SelectedValue='<%# Bind("SelectedValue")%>' >

And this is my ascx:
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="Dropdown.ascx.cs" Inherits="Usercontrol_Dropdown" %>

<script type="text/javascript">
function validate() {
var itoken = document.getElementById('<%=ddlRegion.ClientID%>').options[document.getElementById('<%=ddlRegion.ClientID%>').selectedIndex].value;
if (itoken == "--Select--") {
alert("Select a Region");
return false;
/// is there any way to pass value of itoken to aspx and make use of that??? ///


<asp:DropDownList ID="ddlRegion" runat="server">

The javascript written in ascx works fine when i make use of it with an aspx which have no reference to master page. What u said is correct-because when i tried to use that id(ddlRegion),it returns error.....ie. object is undefined or null.
Please make me clear with these concepts..
Vinu Tuesday, January 25, 2011
Any solution???
Gravatar scott Tuesday, January 25, 2011
Take a look at the HTML source produced by the page - you'll see the different client ID.
Gravatar Prasad, N Wednesday, January 26, 2011
Hi... Scott,

Excellent article...
Vinu Tuesday, February 15, 2011
Finally i got the solution...
Ranji Tuesday, February 15, 2011
can u help me in showing a user friendly message while throwing exceptions--I am using exception handling application block--how can i do that using replace handler??
I have used,
exceptionMessage="An error has occured, contact admin". Can i have this in an alert box. Am using web application C#, .net 4.0

If possible plz help me out......
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