WPF MouseDown / MouseUp Command
Maybe you wanted to bind a command to the MouseDown Event of the Button.
But there is just the Command for the Click Event. Therefore it is necessary to do a little bit of coding.
I usually need the MouseDown / MouseUp Events of the Button for several use cases.
Therefore I just created a simple behavior which contains two command properties (on for the MouseUp and one for the MouseDown event).
The MouseCommandBehavior class looks like this
public static class MouseCommandBehavior
{
#region Commands
///
/// The comamnd which should be executed when the mouse is down
///
public static readonly DependencyProperty MouseDownCommandProperty =
DependencyProperty.RegisterAttached("MouseDownCommand",
typeof(ICommand),
typeof(MouseCommandBehavior),
new FrameworkPropertyMetadata(null, (obj, e) => OnMouseCommandChanged(obj, (ICommand)e.NewValue, false)));
///
/// Gets the MouseDownCommand property
///
public static ICommand GetMouseDownCommand(DependencyObject d)
{
return (ICommand)d.GetValue(MouseDownCommandProperty);
}
///
/// Sets the MouseDownCommand property
///
public static void SetMouseDownCommand(DependencyObject d, ICommand value)
{
d.SetValue(MouseDownCommandProperty, value);
}
///
/// The comamnd which should be executed when the mouse is up
///
public static readonly DependencyProperty MouseUpCommandProperty =
DependencyProperty.RegisterAttached("MouseUpCommand",
typeof(ICommand),
typeof(MouseCommandBehavior),
new FrameworkPropertyMetadata(null, new PropertyChangedCallback((obj, e) => OnMouseCommandChanged(obj, (ICommand)e.NewValue, true))));
///
/// Gets the MouseUpCommand property
///
public static ICommand GetMouseUpCommand(DependencyObject d)
{
return (ICommand)d.GetValue(MouseUpCommandProperty);
}
///
/// Sets the MouseUpCommand property
///
public static void SetMouseUpCommand(DependencyObject d, ICommand value)
{
d.SetValue(MouseUpCommandProperty, value);
}
#endregion
///
/// Registeres the event and calls the command when it gets fired
///
private static void OnMouseCommandChanged(DependencyObject d, ICommand command, bool isMouseUp)
{
if (command == null) return;
var element = (FrameworkElement)d;
if(isMouseUp)
element.PreviewMouseUp += (obj, e) => command.Execute(null);
else
element.PreviewMouseDown += (obj, e) => command.Execute(null);
}
}
}
I hardcoded in this class these two events. But you could even add your own ones 
In the XAML-Code you can use it like that
<button>
If you want a even more flexible approach where you can register just one Command then you can use the behavior of Sacha Barber.
Check this out WPF : Attached Commands
I attached a zip file (remove the .doc extension) which contains a complete project. It is slightly different then what I explained above but the idea is the same.
Hi,
This is a great example, and just what I was looking for… so thanks!
However, two problems that I saw:
1) There is a compilation error in MouseCommandBehavior.OnMouseCommandChanged: “The name ‘routedEventName’ does not exist in the current context”.
2) I have omitted this line and compilation is OK, but the application is not working, and nothing is happening when clikcing the ‘Click me’ button. I have also set a breakpoint in the ‘OnMouseCommandChanged’ method, but I never reches there.
Here is how my xaml looks like:
As you can see, all I did was adding a button to a grid, and set a binding to the ‘MouseDownCommand’ and ‘MouseUpCommand’ properties. In the xaml.cs file the constructor of Window1 looks like this:
public Window1()
{
InitializeComponent();
mMyCommand = new MyCommand();
DataContext = this;
}
Any clue what am I missing in order to make this example fully compiled and working?
Thanks again,
Elad
For some reason the xaml was not published:
Hi,
This is exactly the example I was looking for, so thanks a lot for the snippet.
However, two problems I have:
1) I have a compilation error in the ‘OnMouseCommandChanged’ method – the routeEventName is not recognized by the compiler. Once I have remarked this line compilation is completed successfully.
2) Once I am running the application with the xaml example you gave, nothing is happening in the button when clicking it. I even tried adding a breakpoint in the OnMouseCommandChanged method, but I don’t reach there.
This is how the xaml looks like:
And when more thing, in the constructor of the main window I have set ‘DataContext = this’.
Am I missing something here? Any chance you can give a full example?
Thanks again,
Elad
Hi,
sorry for the slow reply but I was not online yesterday.
The problem is that I had a working version (the file attached on the bottom) then I modified it a bit for the blog. But the modifications introduced this bug
Just download the file and extract it.
Have fun!
Michael
Michael,
I’m terribly sorry for my late respond…
I have downloaded the sample and it’s working now. However, I still need to find some time to analyze it and understand what you did. Since I’m new to WPF things are a little bit slow for me…
I’ll write soon.
Elad
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