启用/禁用菜单项-Expression Blend

Question

I need to disable a particular menuitem when it is clicked. How can I write the code for this within the event handler?

Answer 1

Codebehind event handler:

private void MenuItem_Click(object sender, RoutedEventArgs e)
{
   ((MenuItem)sender).IsEnabled = false;
}

"sender" is the item clicked, we need to cast it to MenuItem to be able to set its IsEnabled property.

Here's how to wire up the event handler in your xaml: In WPF how to add menu item event?

Answer 2

You can do it from the code behind or use an event trigger (which is usually my preferred option for very simple tasks, as you can define them as a resource and reuse).

Code Behind Answer:

<MenuItem Header="Click Me" Click="MenuItem_Click">

---

private void MenuItem_Click(object sender, RoutedEventArgs e)
{
   var menuItem = sender as MenuItem;
   if (menuItem != null) menuItem.IsEnabled = false;
}

XAML Only Answer:

<MenuItem Header="Click Me">
    <MenuItem.Triggers>
        <EventTrigger RoutedEvent="MenuItem.Click">
            <BeginStoryboard>
                <Storyboard>
                    <BooleanAnimationUsingKeyFrames Storyboard.TargetProperty="(MenuItem.IsEnabled)">
                        <DiscreteBooleanKeyFrame KeyTime="0" Value="False" />
                    </BooleanAnimationUsingKeyFrames>
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </MenuItem.Triggers>
</MenuItem>