Error in a .g.cs file?

Error   1   The type or namespace name 'BreadcrumbLib' could not be found (are you missing a using directive or an assembly reference?) YOU_CAN'T_KNOW_THE_PATH_OR_NAME.g.cs    16  7   someWPFapp

And the troublesome line is:

using BreadcrumbLib;

Yesterday I have removed that project (BreadcrumbLib) from my solution and the main project worked fine.
Today it doesn't work.

What can I do about this?
What piece of forsaken information makes Visual Studio or whatever program builds the .g.cs files put that reference there?

Solution 1:

Try doing a clean. If that doesn't work, delete the bin obj directories in your solution, then do a full rebuild. Make sure none of your XAML files are referencing that component (which is what's generating the .g.cs file).

Solution 2:

The .g.cs files in my projects are typically generated from XAML.

Check that the BreadcrumbLib isn't referenced in the xmlns references in any of your XAML files.