Visual Studio 2008 C# project now can't find my references -- likely causes?

Question

Hi everyone,

I'm using VS 2008. In one of our web projects, for some reason, I'm suddenly getting yellow exclamation marks indicating missing references. I'm not sure why.

If I look at the .csproj file in a text editor the references in question are in the project folder structure, tucked in a subfolder, and sure enough that folder and supporting files are there, as they always have been.

Here's a sample of one of the troublesome references, as shown in two places (the only two) in the project file where it's mentioned:

  <ItemGroup>
    <Reference Include="AjaxControlToolkit, Version=3.0.20820.30875, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e, processorArchitecture=MSIL"/>


<Content Include="ThirdParty\AjaxControlToolkit.dll" />

There is a ThirdParty folder in the project, and the appropriate version of AjaxControlToolkit.dll is in there. The project's settings haven't changed, to my knowledge, so I'm at a loss why all these references are supposedly missing. Would anyone know how I might diagnose this?

Answer 1

The easiest/quickest thing to do is remove/re-add the reference.

Would be interested to know what happened, though.

Answer 2

As it turns out, this was due to some instability in my system-- when I closed VS and reopened the project, things worked just fine.