I have to create in my XAML file a static resource.
<Window.Resources>
<vm:ViewModel x:Key="viewModel" />
</Window.Resources>
I need this static resource to get the items for my combobox
ItemsSource="{Binding Source={StaticResource viewModel}, Path=GetItems, Mode=TwoWay}"
But how can I give the ViewModel (constructor) a instance of my code behind class?