The type or namespace does not exist

Question

Ok, I have had this one a million times before and it\'s been answered 1 million +1 times before.

And yet, once again. I have 3 projects, A, B, and C, each a DLL. Each

Answer 1

Create clean project and test minimal sets of assemblies you use in your project. This way you will be sure if there is something bad in your solution or if newly created project has same symptoms. If so, then maybe VS, .net etc is corrupted or something.

Answer 2

With VS2017, this issue came up for me when the project in my solution was unloaded.

Answer 3

I know this isn't the answer to your issue, but the error is quite similar when you are trying to reference a project with a higher .net version than the one you're using. IE: you can't reference something with .net 4.5 from .net 3.5

Answer 4

Go to warning section and resolve all warning and you are done...

The warning section will tell you what all internal dlls dependencies are needed for the project you are referencing to.

Answer 5

I got this when updating a project that we normally use via NuGet. I thought if I simply copied the updated built dll over to the packages folder I could test it without having to setup NuGet on my machine, but it wasn't that simple because my app was still looking for the old version number. Hope that helps someone out there.

Answer 6

I started getting this error suddenly while trying to solve another problem

I solved this by going to Solution=>properties=>project dependencies and all the dependencies were off for the two projects I was getting a namespace error for. I checked the check boxes and rebuilt the solution with no errors.