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

<dxsch:OptionsContextMenu.AppointmentContextMenuActions>
        <!--Insert the "Recurrence" item invoking the Recurrence dialog-->
        <dxb:InsertAction Index="-1">
            <dxb:BarButtonItem Content="Recurrence" 
                               Glyph="{dx:DXImage Image=Recurrence_32x32.png}"                                               
                               Command="{Binding ElementName=schedulerCommands, Path=OpenRecurrenceWindowCommand}">
            </dxb:BarButtonItem>
        </dxb:InsertAction>
        <!--Insert the check item which converts the selected appointment to an all day event-->
        <dxb:InsertAction>
            <dxb:BarCheckItem x:Name="allDayCheck" 
                              Content="All-Day Appointment" 
                              Glyph="{dx:DXImage Image=Check_16x16.png}" 
                              CheckedChanged="allDayCheck_CheckedChanged"/>
        </dxb:InsertAction>
</dxsch:OptionsContextMenu.AppointmentContextMenuActions>

<dxsch:OptionsContextMenu.TimeRulerContextMenuActions>
        <!--Hide the "New All Day Event" and "New Recurring Event" items-->
        <dxb:UpdateAction ElementName="{x:Static Member=dxsch:DefaultBarItemNames.ContextMenu_Items_TimeRuler_Actions_NewAllDayEvent}" 
                          PropertyName="IsVisible" 
                          Value="False"/>
        <dxb:UpdateAction ElementName="{x:Static Member=dxsch:DefaultBarItemNames.ContextMenu_Items_TimeRuler_Actions_NewRecurringEvent}" 
                          PropertyName="IsVisible" 
                          Value="False"/>
    <!--Disable the "New Appointment" and "New Recurring Appointment" item-->
        <dxb:UpdateAction ElementName="{x:Static Member=dxsch:DefaultBarItemNames.ContextMenu_Items_TimeRuler_Actions_NewAppointment}" 
                          PropertyName="IsEnabled" 
                          Value="False"/>
        <dxb:UpdateAction ElementName="{x:Static Member=dxsch:DefaultBarItemNames.ContextMenu_Items_TimeRuler_Actions_NewRecurringAppointment}" 
                          PropertyName="IsEnabled" 
                          Value="False"/>
</dxsch:OptionsContextMenu.TimeRulerContextMenuActions>

<dxsch:OptionsContextMenu.AppointmentDropContextMenuActions>
    <!--Remove the "Copy" item-->
    <dxb:RemoveAction ElementName="{x:Static Member=dxsch:DefaultBarItemNames.ContextMenu_Items_AppointmentDrop_Actions_CopyAppointmentsOnDrop}"/>
</dxsch:OptionsContextMenu.AppointmentDropContextMenuActions>

<dxsch:OptionsContextMenu.CellContextMenu>
    <dxb:PopupMenu>
        <dxb:PopupMenu.Items>
            <dxb:BarButtonItem Content="Add Broadcast..." 
                               Glyph="{dx:DXImage Image=Appointment_16x16.png}" 
                               Command="{Binding ElementName=schedulerCommands, Path=ShowNewAppointmentWindowCommand}"/>
            <dxb:BarButtonItem Content="Add News Block..." 
                               Glyph="{dx:DXImage Image=RecurringAppointment_16x16.png}" 
                               Command="{Binding ElementName=schedulerCommands, Path=ShowNewRecurringAppointmentWindowCommand}"/>
        </dxb:PopupMenu.Items>
    </dxb:PopupMenu>
</dxsch:OptionsContextMenu.CellContextMenu>