The name "X" does not exist in the namespace "using:Y"

Question

After reading every article here and trying every suggested action I'm out of things to try:

I have a namespace issue in Visual Studio 2015 - in a XAML file in UWP. The concrete error message is:

"The name "FieldManagementViewModel" does not exist in the namespace "using:StudyConfigurationClient.ViewModels"".

This is my XAML:

This is the structure to show, that the folder and file actually exists, folder structure equals namespaces in this project:

I've looked all references and namespaces through, I've repaired Visual Studio 2015, I've cleaned and rebuilt several times and changed platform for the build back and forth - I'm out of options.

Answer 1

What worked for me:

1. Remove the problematic XAML tag, so that solution will build
2. Rebuild project
3. Restore the tag

I think VS falls into a chicken & egg situation here, in that it needs newly added classes built so that XAML can see them, but it can't build them because XAML can't see them.

Answer 2

只需将此解决方案添加到此问题： - 关闭并重新打开 Visual Studio

Answer 3

In my case the problem occurred in App.xaml. In the properties for App.xaml the BuildAction had somehow been changed to Page . After restoring the BuildAction to ApplicationDefinition the problem went away. (See also this related answer .)

Answer 4

Thanks for helping - this issue magically went away when I pulled a change from git, which shouldn't affect this in any way. Sorry for not being able to help others, but I haven't got a clue about what happened.