您可以这样做

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Assets/StyleDictionary.xaml"/>
        </ResourceDictionary.MergedDictionaries>
        <!--<ObjectDataProvider x:Key="SAG_POK" ObjectType="{x:Type or:SAG_POK}" />-->
        <local:MainViewModel x:Key="SAG_POK" />
    </ResourceDictionary>        
</Application.Resources>


<StackPanel DataContext="{Binding Source={StaticResource SAG_POK}}">
   <TextBlock Name="ValgtSag" Text="{Binding ToStringProperty}"/>
</StackPanel>

App.Current.Resources["SAG_POK"].SelectedItem = SagSelectedItem;

MainViewModel是孔应用程序中的主视图模型:-)

MainViewModel is yout main view model :-) in the hole application

希望这会有所帮助