<UserControl.Resources>
        <DataTemplate DataType="{x:Type vm:ViewModel1}">
            <vw:View1 />
        </DataTemplate>

        <DataTemplate DataType="{x:Type vm:ViewModel2}">
            <WindowsFormsHost>
                <wfc:SomeWindowsFormsControl  />
            </WindowsFormsHost>
        </DataTemplate>
    </UserControl.Resources>