public ContextMenuType MenuType { get; }

Public ReadOnly Property MenuType As ContextMenuType

private void scheduler_PopupMenuShowing(object sender, PopupMenuShowingEventArgs e)
{
    //Customize the cell context menu:
    if (e.MenuType == ContextMenuType.CellContextMenu)
    {
        PopupMenu menu = (PopupMenu)e.Menu;

        //Change the "New All Day Event" item's caption to "Create All-Day Appointment":
        for (int i = 0; i < menu.Items.Count; i++)
        {
            BarItem menuItem = menu.Items[i] as BarItem;
            if (menuItem != null)
            {
                if (menuItem != null && menuItem.Content.ToString() == "New All Day Event")
                {
                    menuItem.Content = "Create All-Day Appointment";
                    break;
                }
            }
        }
        //Add new menu item: 
        if (!menu.Items.Contains(myMenuItem))
        {
            CreateNewItem();
            menu.Items.Add(myMenuItem);
        }
    }
}
private void CreateNewItem()
{
    //Create a new menu item: 
    myMenuItem = new BarButtonItem();

    myMenuItem.Name = "customItem";
    myMenuItem.Content = "Item Added at Runtime";
    myMenuItem.ItemClick += new ItemClickEventHandler(customItem_ItemClick);
}
private void customItem_ItemClick(object sender, ItemClickEventArgs e)
{
    // Implement a custom action. 
    MessageBox.Show(String.Format("{0} is clicked", e.Item.Name));
}

Private Sub scheduler_PopupMenuShowing(ByVal sender As Object, ByVal e As PopupMenuShowingEventArgs)
    'Customize the cell context menu:
    If e.MenuType = ContextMenuType.CellContextMenu Then
        Dim menu As PopupMenu = CType(e.Menu, PopupMenu)

        'Change the "New All Day Event" item's caption to "Create All-Day Appointment":
        For i As Integer = 0 To menu.Items.Count - 1
            Dim menuItem As BarItem = TryCast(menu.Items(i), BarItem)
            If menuItem IsNot Nothing Then
                If menuItem IsNot Nothing AndAlso menuItem.Content.ToString() = "New All Day Event" Then
                    menuItem.Content = "Create All-Day Appointment"
                    Exit For
                End If
            End If
        Next i
        'Add new menu item: 
        If Not menu.Items.Contains(myMenuItem) Then
            CreateNewItem()
            menu.Items.Add(myMenuItem)
        End If
    End If
End Sub
Private Sub CreateNewItem()
    'Create a new menu item: 
    myMenuItem = New BarButtonItem()

    myMenuItem.Name = "customItem"
    myMenuItem.Content = "Item Added at Runtime"
    AddHandler myMenuItem.ItemClick, AddressOf customItem_ItemClick
End Sub
Private Sub customItem_ItemClick(ByVal sender As Object, ByVal e As ItemClickEventArgs)
    ' Implement a custom action. 
    MessageBox.Show(String.Format("{0} is clicked", e.Item.Name))
End Sub

//Customize the cell context menu:
if (e.MenuType == ContextMenuType.CellContextMenu) {
    PopupMenu menu = (PopupMenu)e.Menu;

'Customize the cell context menu:
If e.MenuType = ContextMenuType.CellContextMenu Then
    Dim menu As PopupMenu = CType(e.Menu, PopupMenu)