Question

I want to set two shortkeys for two buttons with one shortkey name.
How can i detect which control is focused in MVVM ?

Answer 1

You can simply add the hotkey to whatever scope is logical for it to exist in. There are many ways to handle hotkeys to WPF, however your basic markup should look something like this:

<Window>
    <StackPanel>
        <local:MyUserControlA>
            <local:MyUserControlA.InputBindings>
                <KeyBinding Key="Enter" Command="{Binding SaveACommand}" />
            </local:MyUserControlA.InputBindings>
        </local:MyUserControlA>

        <local:MyUserControlB>
            <local:MyUserControlB.InputBindings>
                <KeyBinding Key="Enter" Command="{Binding SaveBCommand}" />
            </local:MyUserControlB.InputBindings>
        </local:MyUserControlB>

    </StackPanel>
</Window>

This will run SaveACommand if UserControlA has keyboard focus, or SaveBCommand if UserControlB has keyboard focus.