How to add horizontal separator in a dynamically created ContextMenu?

Question

I was looking for the solution on the internet but was not able to find it within my sample. I need to add a separator between Context menu item that are generated from code behind. I tried to add it with such code lines like below but without success.

this.Commands.Add(new ToolStripSeparator()); 

I am wondering if someone can help. Thank you in advance.

Context Menu XAML:

<Style x:Key="DataGridCellStyle" TargetType="{x:Type DataGridCell}">
    <Setter Property="ContextMenu">
        <Setter.Value>
            <ContextMenu ItemsSource="{Binding Commands}">
                <ContextMenu.ItemContainerStyle>
                    <Style TargetType="{x:Type MenuItem}">
                        <Setter Property="Command" Value="{Binding}" />
                        <Setter Property="Header" Value="{Binding Path=Text}" />
                        <Setter Property="CommandParameter" Value="{Binding Path=Parameter}" />
                    </Style>
                </ContextMenu.ItemContainerStyle>
            </ContextMenu>
        </Setter.Value>
    </Setter>

C# that added in the method:

this.Commands = new ObservableCollection<ICommand>();
        this.Commands.Add(MainWindow.AddRole1);
        this.Commands.Add(MainWindow.AddRole2);
        this.Commands.Add(MainWindow.AddRole3);
        this.Commands.Add(MainWindow.AddRole4);
        //this.Add(new ToolStripSeparator()); 
        this.Commands.Add(MainWindow.AddRole5);
        this.Commands.Add(MainWindow.AddRole6);
        this.Commands.Add(MainWindow.AddRole7); 

Answer 1

I did this once and used a null as my separator. From the XAML, I then styled the template to use a separator if the datacontext was null

Code behind:

this.Commands.Add(MainWindow.AddRole4);
this.Add(null); 
this.Commands.Add(MainWindow.AddRole5);

XAML was something like this:

<ContextMenu.ItemContainerStyle>
    <Style TargetType="{x:Type MenuItem}">
        <Setter Property="Command" Value="{Binding}" />
        <Setter Property="Header" Value="{Binding Path=Text}" />
        <Setter Property="CommandParameter" Value="{Binding Path=Parameter}" />

        <Style.Triggers>
            <DataTrigger Binding="{Binding }" Value="{x:Null}">
                <Setter Property="Template" Value="{StaticResource MenuSeparatorTemplate}" />
            </DataTrigger>
        </Style.Triggers>
    </Style>
</ContextMenu.ItemContainerStyle>

Hope I got the syntax right - I don't have an IDE on this machine to verify the code

EDIT

Here is an example template for the context menu separator. I am putting it in ContextMenu.Resources, although you could put this anywhere you want in your application as long as the ContextMenu can access it.

<ContextMenu.Resources>
    <ControlTemplate x:Key="MenuSeparatorTemplate">
        <Separator />
    </ControlTemplate>
</ContextMenu.Resources>