Removing "ctl" prefix on HTML id attributes (code
included)

It's always bugged me that ASP.NET adds "ctlXXX_" to my HTML element
id attributes.  It's particularly irritating because some elements I've defined
CSS styles specifically for them, and for ASP.NET to do so breaks that styling. 
I put in some time this afternoon to write some code to eliminate that behavior.
 This little snippet implements a derived class, ExtendedUserControl which
catches the RenderControl method and uses a Regular Expression to replace the
misshapen ID tag.  Using the RegEx enables underscores ("_") to still
be used in id tag names, as it only grabs the ctlXXX_ instances.

How to use this:

Create a new class in your App_Code folder called
"ExtendedUserControl.cs"
Copy and paste the code from below into this new class.

Create a new "Web User Control"
Change the UserControl inheritance to ExtendedUserControl


For VB.NET:  Change "Inherits System.Web.UI.UserControl" to
"Inherits ExtendedUserControl"

For C#.NET:  Change " : System.Web.UI.UserControl" to " :
ExtendedUserControl"

  

 That's it.  Happy coding.  (Tested with .NET framework 2.0)


  


1    using System;
2    using System.IO;
3    using System.Text.RegularExpressions;
4    using System.Data;
5    using System.Configuration;
6    using System.Web;
7    using System.Web.Security;
8    using System.Web.UI;
9    using System.Web.UI.HtmlControls;
10   using System.Web.UI.WebControls;
11   using System.Web.UI.WebControls.WebParts;
12   13   /// <summary>
14   /// Extended User Control that doesn't botch the HTML id attribute.
15   /// </summary>16   17   public partial class ExtendedUserControl :
System.Web.UI.UserControl
18   {
19   public override void RenderControl(HtmlTextWriter writer)
20       {
21   // Render the control, placing the output in a string22          
StringWriter sw = new StringWriter(new System.Text.StringBuilder(),
23               System.Globalization.CultureInfo.InvariantCulture);
24           HtmlTextWriter htw = new HtmlTextWriter(sw);
25   base.RenderControl(htw);
26   string chtml = sw.ToString();
27           sw.Close();
28   29   // Match HTML id attributes that start with 'ctl'30           Regex r
= new
Regex(@"\sid=""ctl[0-9]*_[A-Za-z][A-Za-z0-9]*""");

31   32   // Remove ASP.NET's adjusted id tag prefix33   foreach (Match m in
r.Matches(chtml))
34           {
35   //this.Response.Write(Regex.Replace(m.Value, @"ctl[A-Za-z0-9]*_",
"") + "<br/>");36               chtml =
chtml.Replace(m.Value, Regex.Replace(m.Value, @"ctl[A-Za-z0-9]*_",
""));
37           }
38   39   this.Response.Write(chtml);
40       }
41   }