Visual Studio displays many errors, but there is only one actual error

I have a custom control library in my solution where my main WPF project is referencing it. If there is an error in the custom control library, then the error list goes into a skill state and displays hundreds of errors. Here is an example of one such incident.

Now, this is just a bug that caused me to force it to demonstrate the problem.

In this case, the problem is not as serious as there are only 21 errors. However, there have been cases where I had to filter hundreds of errors to find the actual error that caused everything else to fail.

I believe I understand what the problem really is. I think the problem is because the custom control library is not being built , so my main project cannot find the DLL for it, and so the custom controls cannot be found, which is causing errors.

Now, in truth, the list of errors does not lie, I mean, these are real errors. However, speaking of which, is there a way to prevent this?