Silverlight: DataGrid and Comboxbox with MVVM

If you are using a MVVM pattern with a view model you have generally the problem to bind a combobox inside a Datagrid because you cannot access the data context of your view by referencing with the elementname syntax. The trick to bind your Comboxbox inside a DataGridTemplateColumn is to define the reference to your viewmodel with a StaticResoucre and use this for the DataContext-Binding and combobox-Binding:

StaticResoucre of the viewmodel

   1:  

   2:     <controls:ChildWindow.Resources>

   3:         <ViewModels:SettingsViewModel x:Key="SettingsViewModel" />

   4:     </controls:ChildWindow.Resources>

Binding the view to your viewmodel

   1: <Grid x:Name="LayoutRoot" Margin="2" DataContext="{StaticResource SettingsViewModel}">

Combobox-Binding in the Datagrid

   1: <sdk:DataGridTemplateColumn.CellEditingTemplate>

   2:     <DataTemplate>

   3:         <ComboBox ItemsSource="{Binding Gesellschaften,Source={StaticResource SettingsViewModel}}" 

   4:                   DisplayMemberPath="Name" SelectedValue="{Binding GesellschaftId, Mode=TwoWay}" 

   5:                   SelectedValuePath="GesellschaftId"  />

   6:     </DataTemplate>

   7: </sdk:DataGridTemplateColumn.CellEditingTemplate>