I'm using MVVM.
<ItemsControl ItemsSource="{Binding AllIcons}" Tag="{Binding}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel>
<Label HorizontalAlignment="Right">x</Label>
<Image Source="{Binding Source}" Height="100" Width="100" />
<Label HorizontalAlignment="Center" Content="{Binding Title}"/>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
That looks fine. If I put a button in the stack panel using this command:
<Button Command="{Binding开发者_开发技巧 Path=DataContext.InvasionCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}}" CommandParameter="{Binding}"/>
I'm able to capture the command. However, I want to execute the command binding when the mouse enters the stack panel, not when I click a button.
Any idea?
My wrong, input bindings does not solve the problem. You may use attached properties for this:
public static class MouseEnterCommandBinding
{
public static readonly DependencyProperty MouseEnterCommandProperty = DependencyProperty.RegisterAttached(
"MouseEnterCommand",
typeof(ICommand),
typeof(MouseEnterCommandBinding),
new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsRender)
);
public static void SetMouseEnterCommand(UIElement element, ICommand value)
{
element.SetValue(MouseEnterCommandProperty, value);
element.MouseEnter += (s,e) =>
{
var uiElement = s as UIElement;
var command = GetMouseEnterCommand(uiElement);
if (command != null && command.CanExecute(uiElement.CommandParameter))
command.Execute(uiElement.CommandParameter);
}
}
public static ICommand GetMouseEnterCommand(UIElement element)
{
return element.GetValue(MouseEnterCommandProperty) as ICommand;
}
}
First you need to declare a behavior for mouse enter. This basically translates the event into a command in your ViewModel.
public static class MouseEnterBehavior
{
public static readonly DependencyProperty MouseEnterProperty =
DependencyProperty.RegisterAttached("MouseEnter",
typeof(ICommand),
typeof(MouseEnterBehavior),
new PropertyMetadata(null, MouseEnterChanged));
public static ICommand GetMouseEnter(DependencyObject obj)
{
return (ICommand)obj.GetValue(MouseEnterProperty);
}
public static void SetMouseEnter(DependencyObject obj, ICommand value)
{
obj.SetValue(MouseEnterProperty, value);
}
private static void MouseEnterChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
UIElement uiElement = obj as UIElement;
if (uiElement != null)
uiElement.MouseEnter += new MouseEventHandler(uiElement_MouseEnter);
}
static void uiElement_MouseEnter(object sender, MouseEventArgs e)
{
UIElement uiElement = sender as UIElement;
if (uiElement != null)
{
ICommand command = GetMouseEnter(uiElement);
command.Execute(uiElement);
}
}
}
Then you just need to create that command in your view model and reference it in the view. The behaviors: namespace should just point to wherever you created that behavior. I use this pattern every time I need to translate an event into a command in a view model.
<Grid>
<StackPanel behaviors:MouseEnterBehavior.MouseEnter="{Binding MouseEnteredCommand}"
Height="150"
Width="150"
Background="Red">
</StackPanel>
</Grid>
You probably need to use InputBindings: http://msdn.microsoft.com/en-us/library/system.windows.input.inputbinding.aspx
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