Generation of designer file failed: Could not load file or assembly

Question

I have an ASP.NET web application project which references another project called ModusCore (or Modus.Core). We\'ve had a variety of controls that use ModusCore up until now wi

Answer 1

Another solution I have found to be effective in Visual Studio 2015 is to close VS and then clear out the following directories:

• %UserProfile%\AppData\Local\Temp\Temporary ASP.NET Files\
• %UserProfile%\AppData\Local\Microsoft\VisualStudio\14.0\ProjectAssemblies\

Open your solution again and select Build->Clean Solution.

Now go to your ASPX page, and then select Project->Convert To Web Application

Answer 2

Adding a third option for when @scherand's (a) and (b) fail:

c) "Sometimes", this works as well:

• Remove the <%@ Register... %> entries
• Save the .AS?X file. Let the designer complain.
• Add the <%@ Register... %> again
• Save again

[Added Oct-13-2010]:
d) "Sometimes", as well:

• Clear the AS?X file off all but the most basic content.
• Start adding pieces back, one bit a time.
• Save.
• Check that you didn't get the error message.
• Add back a few more pieces. Rinse. Repeat.

I use a text comparison tool against a back up copy of the AS?X file for this.

I try to avoid adding the controls that cause the error until the very end. I also try to add from the bottom of the page. However, I don't know of a hard rule. It's a gut-feeling exercise.

(Will someone ever figure this one out?)

Answer 3

I have a very similar problem (which I could not solve yet). The Application I have the problem with was converted from a "Web Site Project" though and I can't get rid of the feeling that this has something to do with it. And I am on VS 2005.

Now what I can add is that

a) "sometimes" (I could not figure out when exactly yet) the "Convert to Web Application"-trick works for me (but not always)

b) "sometimes" (same as above) it helps to switch to the designer view, change something and save -> *.designer.cs gets regenerated

I usually try several things in no fix order after I added a control to my page until "something" works.

There is a lot of noise about this on the internet but I could not find a "real fix" for it (yet). One thing I read besides the already mentioned is that it could have something to do with (not matching/not existing) namespaces.

When I checked my application there really were no namespace declarartions in the *.cs-files. So I added them (in *.cs and *.aspx) and for some time thought it did the trick. But sadly by now I know that this was not the case...