does not find user control in namespace
everywhere, even on the book I bought, it says that to create a custom control I have to create a folder, add a user control, declare the namespace on the page and then I can use it. There are no other errors
I was able to solve the problem by creating a new project, creating the controls, and copying and pasting the controls code. I probably unintentionally removed some files or settings or there was a bug.