Routing Strategies:
- Direct
- Bubbling
- Tunneling
WHy use them?
- Any UIElement can be a listener
- Common handlers
- Visual Tree Communication
- Event Setter and Event Trigger
Routed Event Example:
<Window x:Class="CustomControlDemo.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Width="350"
Height="220"
ButtonBase.Click="Window_Click"> //listen to the RoutedEvent：ButtonBase.Click and handle RoutedEvent using Window_Click
<Grid>
<StackPanel Margin="20" ButtonBase.Click="StackPanel_Click"> //listen to the RoutedEvent：ButtonBase.Click and handle RoutedEvent using StackPanel_Click
<Border BorderBrush="Red" BorderThickness="5">
<TextBlock Margin="5"
FontSize="18"
Text="This is a TextBlock" />
</Border>
<Button Margin="10"
Click="Button_Click" //handle the Button.Click event using Button_Click handler
Content="Click me" />
</StackPanel>
</Grid>
</Window>
namespace CustomControlDemo
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
} private void Button_Click(object sender, RoutedEventArgs e)
{
//Button层的event handler，由于ButtonBase.Click是routedEvent所以可以向上bubble
} private void StackPanel_Click(object sender, RoutedEventArgs e)
{
e.Handled = true; //StackPanel层的event handler，不继续向上传
e.Handled = false; //StackPanel层的event handler，继续向上传
} private void Window_Click(object sender, RoutedEventArgs e)
{
//Window层的event handler，已传到最上层
}
}
}
我们也可以不在xaml写handler，直接用后台控制
namespace CustomControlDemo
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
AddHandler(Button.ClickEvent, new RoutedEventHandler(Window_Click), true); //即使e.Handled = true;我们也要routedevent继续传到window层
} private void Button_Click(object sender, RoutedEventArgs e)
{
//Button层的event handler，由于ButtonBase.Click是routedEvent所以可以向上bubble
} private void StackPanel_Click(object sender, RoutedEventArgs e)
{
e.Handled = true;
} private void Window_Click(object sender, RoutedEventArgs e)
{
}
}
}
Custom Routed Events
- register your event
- choose your routing strategy
- provide add and remove CLR wrapper
- Raise your event