How does ASP.NET Webforms decide HTML name of a control?

Question

In ASP.NET web forms when a control is rendered on the page, the ID of each field is modified with the ctrl01 as needed to ensure collisions don't happen (aka myField becomes ctrl01$myField or whatnot).

I was wondering where one might find details on HOW the algorithm itself works, or where it might be I can find it. I am assuming the INamingContainer has something to do with this-- but alas I cannot find the part which actually decides the rendered field name.

Any help would be awesome!

Answer 1

You are probably looking for this msdn article.

Answer 2

It's based on the hierarchical layout of the webpage. But you can control this with the ClientId property.

So a textbox in a usercontrol will be named ctrl01#textboxname (Like you said in your post)

Answer 3

Apart from the other answers, if you are using ASP .NET 4, you have much more control over it.

Take a look @ these web pages

http://www.west-wind.com/weblog/posts/54760.aspx

http://weblogs.asp.net/asptest/archive/2009/01/06/asp-net-4-0-clientid-overview.aspx

Answer 4

It concatenates it's own name with your original id.

In ASP.NET 4 you can suppress this concatenation and keep your own id in three different ways:

• Each server control has an attribute called clientIdMode which you can set to Static
• You can also set clientIdMode in the page directive which will affect all controls on the page.
• Or you can set it in the web.config to affect all controls in all pages. (Unless the page or control is set to a different clientIdMode

Note: If you are using AJAX Control Toolkit you will need to set those controls that are part of the toolkit to a clientIdMode of Predictive