K. Scott Allen, one of the many Scotts who seem to develop in .NET, has written a comprehensive article...

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?

"Atlas" April CTP Release [Via: Rich Ersek ]
[T-SQL] Call a stored procedure once for each row in a...

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

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?

Thanks,

Jon

Jon:

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.

Chris:

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.

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! :)

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!!!

do you have anything related with:

Content Page To Master Page Interaction?

thank you

Nisar:

The event will be null until someone subscribes to the event. Typically the page would subscribe to the event (SendEmail += new SendEmailEventHandler(...))

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

Thanks!

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 ?

Thanks
Vani
srivanimk@hotmail.com

Ed: You shouldn't have to "new BaseMaster()" if that is the base class for your master page. It's an inheritance relationship.

A well constructed, useful article - thanks!

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

Trevor

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

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).

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

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.

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.

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.

Scott,
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.

-Vik

Scott,

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. :)

J.P.
zurilgenj@saic.com

Scott,

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!

J.P.

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?

Steve

Thank you for your work on this article; it helped me a great deal.

Scott,
Best "Get under the hood" Master-Mechanic article on MasterPages on the net. Good work.
Appreciate it!

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:

http://groups.google.com/group/microsoft.public.dotnet.framework.aspnet/browse_thread/thread/ed128f111e2fc826/eb862a9635f5ad3e?lnk=st&q=I+want+to+pass+a+string+variable+from+default3.aspx+to+default2.aspx&

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?

Thanks

John

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.

thks

Scott,

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,

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! :-)

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.

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>");

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.

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

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.

-Peter

Best article I've come across concerning Master pages. The section entitled "Headers, Scripts, and Meta Tags, Too" was extremely helpful to me.

Hi,

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)

K. Scott Allen , one of the many Scotts who seem to develop in .NET, has written a comprehensive article

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,

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>

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

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!
Michael

Hi,

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?

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.

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?
Thanks!
ED

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
}

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.

Thoughts?

Hi.
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?

Thanks

Scott,

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?


Ram

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?

Scott,

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

public interface IMasterForm
{
string MasterFieldText
{
get;
}
}

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
{
set
{
lblResult.Text = value;
}
get
{
return lblResult.Text;
}
}

#region IMasterForm Members

public string MasterFieldText
{
get { return setLabel; }
}

#endregion
}

------------------------------

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...)


page1.aspx.cs:


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;
}
}


page1.aspx:

<%@ 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" />
</asp:Content>

---------------

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.