How do you force Visual Studio to regenerate the .designer files for aspx/ascx files?


Sometimes when I'm editing page or control the .designer files stop being updated with the new controls I'm putting on the page. I'm not sure what's causing this to happen, but I'm wondering if there's any way of forcing Visual Studio to regenerate the .designer file. I'm using Visual Studio 2008

EDIT: Sorry I should have noted I've already tried:

  • Closing & re-opening all the files & Visual Studio
  • Making a change to a runat="server" control on the page
  • Deleting & re-adding the page directive
11/2/2008 2:06:26 AM

Accepted Answer

If you open the .aspx file and switch between design view and html view and back it will prompt VS to check the controls and add any that are missing to the designer file.

In VS2013-15 there is a Convert to Web Application command under the Project menu. Prior to VS2013 this option was available in the right-click context menu for as(c/p)x files. When this is done you should see that you now have a *.Designer.cs file available and your controls within the Design HTML will be available for your control.

PS: This should not be done in debug mode, as not everything is "recompiled" when debugging.

Some people have also reported success by (making a backup copy of your .designer.cs file and then) deleting the .designer.cs file. Re-create an empty file with the same name.

There are many comments to this answer that add tips on how best to re-create the designer.cs file.

12/3/2019 8:10:33 PM

Well I found a solution that works, though I don't really like it. I had to delete the .designer.cs file then recreate an empty file with the same name. When I went back in and saved the aspx file again, the designer file was re-generated.



I use the following method which works everytime:

  • Select all of the code-in-front (html markup etc) in the editor of the aspx/ascx file.
  • Cut.
  • Save.
  • Paste.
  • Save.



I recently saw that I was having the same problem. Visual Studio 2010 was refusing to update the designer file.

As it turns out, VS doesn't modify the designer file for a page that uses CodeFile (run off of pages) instead of CodeBehind (DLL). This is true no matter how many times you close VS, reload the project, re-create the control(s), or modify a file. Nothing would prompt VS to regenerate the designer. It's as if it doesn't create the designer file for CodeFile pages but does require it to be there.

I changed it to CodeBehind and saved the page. The designer file updated immediately. Then I just changed it back and everything was still golden. This behavior seems to be new with VS 2010 / .NET 4.0 as VS 2008 by default didn't suffer from this.

It's this part:

<%@ Page Language="vb" AutoEventWireup="false" CodeFile="YourPage.aspx.vb" Inherits="YourPageClass" %>

Change CodeFile to CodeBehind, save, and then revert.


There is another possibility: You may have an error in your .aspx file that does not allow Visual Studio to regenerate the designer.

If you switch to Design View, it will show the control as unable to be rendered. Fixing the control (in my case it was an extra quote in the properties) and recompiling should regenerate the designer.


Most of the solutions here don't work if you're running Visual Studio 2013 and possibly 2012. Microsoft probably introduced some optimizations to make the IDE snappier, consequently they've reduced the number of cases that trigger the code generator. The following scenarios that used to work no longer do:

  1. Delete the aspx or ascx file -- No longer checks for this case
  2. Cut all the content and repaste into the aspx or ascx file -- No longer works, no change in the references
  3. Convert to Web Application -- Option no longer available
  4. Arbitrarily changing content on the aspx/ascx file -- No longer works (see 2).

The solution is surprisingly simple, but it's slightly cumbersome. In order to trigger the code generator, change something that would require the designer.aspx.cs to be generated. Changing content that doesn't affect code, such as a CSS style or adding text, won't trigger the code generator. You must change a referenced control. Here's how to do it:

In the ascx or aspx change the ID of the control

<asp:HyperLink ID="MyLink" runat="server" NavigateUrl="~/Default.aspx" Text="Home" />


<asp:HyperLink ID="theLINK" runat="server" NavigateUrl="~/Default.aspx" CssClass="tab" Text="Home" />

Go to the ascx.cs or aspx.cs and make sure you rename all references to "MyLink" to "theLINK" as well. Save and do build and the you should be good to go.


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