How can I delay loading a control until the RadioButton selection changes?

I have ListBoxone that is used for use RadioButtons, and the change SelectedItemalso changes UserControlwhat is displayed in ContentControlunder it. The application is as follows:

<ListBox ItemsSource="{Binding AvailableViewModels}"
         SelectedItem="{Binding SelectedViewModel}"
         Style="{StaticResource RadioButtonListBoxStyle}" />

<ContentControl Content="{Binding SelectedViewModel}" />

My problem is UserControls, in each of which there is a customizable grid control (Telerik RadGridView), which has a noticeable delay in loading due to the amount of data contained in it.

ItemsSource Loaded Grid, Grid, , , RadioButtons , , UI

DispatcherPriority , , , .

XAML:

<telerik:RadGridView x:Name="MyGrid" Loaded="MyGrid_Loaded" Unloaded="MyGrid_Unloaded">
     <!--....-->
</telerik:RadGridView>

#:

private void MyGrid_Loaded(object sender, RoutedEventArgs e)
{
    this.Dispatcher.BeginInvoke(DispatcherPriority.SystemIdle,
        new Action(delegate()
    {
        BindingOperations.SetBinding(
            MyGrid,
            RadGridView.ItemsSourceProperty,
            new Binding("ViewModelProperty")
        );
    }));
}

private void MyGrid_Unloaded(object sender, RoutedEventArgs e)
{
    MyGrid.ItemsSource = null;
}

, , UserControl, RadioButton , Grid . UserControl , RadioButtons .

- , Views ?

Edit

, , RadioButtons ListBox . ListBox .

XAML:

<Window.Resources>

    <!-- Need two separate DataTemplates -->
    <DataTemplate DataType="{x:Type local:Test}">
        <StackPanel>
            <TextBlock Text="Test" />
            <TextBlock Margin="10" Loaded="TextBlock_Loaded" />
            <TextBlock Text="Test" />
        </StackPanel>
    </DataTemplate>

    <DataTemplate DataType="{x:Type local:Test2}">
        <StackPanel>
            <TextBlock Text="Abc" />
            <TextBlock  Margin="10" Loaded="TextBlock_Loaded" />
            <TextBlock Text="Abc" />
        </StackPanel>
    </DataTemplate>

    <Style x:Key="RadioButtonListBoxStyle" TargetType="{x:Type ListBox}">
        <Setter Property="BorderBrush" Value="Transparent"/>
        <Setter Property="KeyboardNavigation.DirectionalNavigation" Value="Cycle" />
        <Setter Property="ItemsPanel">
            <Setter.Value>
                <ItemsPanelTemplate>
                    <StackPanel Orientation="Horizontal" />
                </ItemsPanelTemplate>
            </Setter.Value>
        </Setter>
        <Setter Property="ItemContainerStyle">
            <Setter.Value>
                <Style TargetType="{x:Type ListBoxItem}" >
                    <Setter Property="Margin" Value="2, 2, 12, 2" />
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate>
                                <Border Background="Transparent">
                                    <RadioButton
                                            Content="{TemplateBinding ContentPresenter.Content}" VerticalAlignment="Center"
                                            ContentTemplate="{Binding RelativeSource={RelativeSource AncestorType={x:Type ListBox}}, Path=ItemTemplate}"
                                            IsChecked="{Binding Path=IsSelected,RelativeSource={RelativeSource TemplatedParent},Mode=TwoWay}"/>
                                </Border>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </Setter.Value>
        </Setter>
    </Style>

</Window.Resources>

<StackPanel>
    <ListBox x:Name="TestListBox"
             ItemsSource="{Binding Test}"
             Style="{StaticResource RadioButtonListBoxStyle}">

        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="Option" />
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

    <ContentControl Content="{Binding ElementName=TestListBox, Path=SelectedItem}" />
</StackPanel>

#:

private void TextBlock_Loaded(object sender, RoutedEventArgs e)
{
    this.Dispatcher.BeginInvoke(DispatcherPriority.ContextIdle,
        new Action(delegate()
        {
            System.Threading.Thread.Sleep(1000);
            ((TextBlock)sender).Text = "Delay Loaded Test";
        }));
}

Test - ObservableCollection<ITest>, Test Test2. , DataTemplate DataTemplate.