左键单击打开按钮ContextMenu

Question

I have a button with a context menu, my requirements are to show the context menu on left click

The problem is that the <ContextMenu ItemsSource="{Binding LineItems}" isn't being updated/refresh when the context menu opens. However If i right click first, items are loaded fine

XAML

<Button  x:Name="BtnMessageChannel" Click="BtnMessageChannel_Click" Grid.Row="0" Grid.Column="2" Height="23" Width="23" ToolTip="Message Channel" >
    <Button.ContextMenu>
        <ContextMenu ItemsSource="{Binding LineItems}" x:Name="CtxMessageChannel">
            <ContextMenu.Resources>
                <Image x:Key="img" Source="{Binding Icon}" x:Shared="false"/>
                <Style TargetType="{x:Type MenuItem}">
                    <Setter Property="Header" Value="{Binding DisplayName}"/>
                    <Setter Property="Icon" Value="{StaticResource img}">
                    </Setter>
                </Style>
            </ContextMenu.Resources>
        </ContextMenu>
    </Button.ContextMenu>
    <Image Source="Images/mail_send.png" HorizontalAlignment="Left" Width="16" />
</Button>

Code Behind

private void BtnMessageChannel_Click(object sender, RoutedEventArgs e)
{
   BtnMessageChannel.ContextMenu.GetBindingExpression(ContextMenu.ItemsSourceProperty)
            .UpdateTarget();  
   BtnMessageChannel.ContextMenu.Visibility = Visibility.Visible;
   BtnMessageChannel.ContextMenu.IsOpen = true;

}

Is there any easy solutions to this problem?

Answer 1

An easy solution is to update your button event handler to simulate a right click if the context menu is not currently open.

    private void BtnMessageChannel_Click(object sender, RoutedEventArgs e)
    {
        if (!BtnMessageChannel.ContextMenu.IsOpen)
        {
            e.Handled = true;

            var mouseRightClickEvent = new MouseButtonEventArgs(Mouse.PrimaryDevice, Environment.TickCount, MouseButton.Right)
            {
                RoutedEvent = Mouse.MouseUpEvent,
                Source = sender,
            };
            InputManager.Current.ProcessInput(mouseRightClickEvent);
        }
    }