C# .NET WinForms。 Visual Studio 无法识别子文件夹中的命名空间

Question

When I create a new folder, in this case Model , as a subfolder to the solution directory, and add a class in there, which is wrapped in a namespace, the namespace cannot be found.

Yes, I have tried both adding a using directive, and referring to the class directly, like Model.Class , from the main source file.

What is going on? In the class explorer, the Model folder is not visible, while it is visible in the solution explorer, it is visible. The other subfolders are visible in the class explorer.

Answer 1

What is the namespace in the class file?

If you have a class file in the Model.Class folder, but the namespace in the file is Model , you still have to use using Model;

Answer 2

Problem solved. The folder and code files in question were not part of the VS project.