How can I make a user control extend a class that extends UserControl?

Question

I want to attempt an MVC design for my little app.

I have a normal Csharp class ViewBase which extends UserControl. It's a single .cs file.

I have multiple classes that I want to extend ViewBase. These are actual UserControls so they have a code behind .cs file and a .xaml file.

However, CSharp tells me that for these classes, their base class "differs from declared in other parts".

Is what I want to do possible at all? What am I doing wrong?

Note that I did not modify my XAML files, so they still use tags.

Here is the relevant code:

// This gives the error in question and ViewBase is underlined
// "Base class of LoginView differs from declared in other parts"
public partial class LoginView : ViewBase {
    public LoginView(Shell shell, ControllerBase controller) : base(shell, controller) {
        InitializeComponent();
    }
}

// This one is a single .cs file
public abstract class ViewBase : UserControl {
    public Shell Shell { get; set; }
    public ControllerBase Controller { get; set; }

    protected ViewBase(Shell shell, ControllerBase controller)
    {
        Shell = shell;
        Controller = controller;
    }
}

Answer 1

Note that I did not modify my XAML files, so they still use tags

That's your problem. You'll need to change:

<UserControl ...>
    ...
</UserControl>

to

<local:ViewBase xmlns:local="clr-namespace:..."
    ...
</local:ViewBase>

The problem is you're telling the compiler you're inheriting ViewBase in one place (the .cs file) and UserControl in another (the .xaml file).