After changing namespace in UserControl files, …g.cs files get errors

Question

I copied three classes in from another WPF project and then changed their namespaces.

Now when I run the project, I get errors in the \".g.cs\"

Answer 1

The .g.cs file is generated from the .xaml file. You need to change the x:class= attribute in your .xaml file to match the new namespace-qualified class name; then the .g.cs will be generated correctly on next compile. (Don't manually change the .g.cs file -- you'll only frustrate yourself.)

For example, if you previously had this in your .cs:

namespace Foo {
    class Bar { ...

and this in your .xaml:

<UserControl x:Class="Foo.Bar" ...

And then you changed your namespace:

namespace Baz {
    class Bar { ...

Then you would need to change your .xaml file to:

<UserControl x:Class="Baz.Bar" ...

Answer 2

I had defined XML namespace shortcuts in my AssemblyInfo.cs

[assembly: XmlnsDefinition("http://www.example.com/wpf", "MyCorp.Wpf.OldNamespace")]

where the old namespace was still present. Searching through all my *.xaml files obviously did not help …

After fixing the shortcuts, the error went away immediately.

Answer 3

I had this issue and tried deleting the obj and bin folders, but that would not work. It finally compiled when I selected Project > Clean and then Project > Build. There must be some Visual Studio cache somewhere else on my system.

Answer 4

Another possible cause is if you have any xmlns:xx namespaces in your xaml which you neglected to update when changing a namespace, then this will also cause an invalid using statement in the g.cs file.

Answer 5

Did you update the namespace of the class in the x:Class attribute on UserControl in the XAML too?

Failing that, have you tried rebuilding the project?

Answer 6

I found another way to solve this by deleting your 'obj' folder and rebuilding.