ButtonBase.OnMouseLeftButtonDown Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Provides class handling for the MouseLeftButtonDown event that occurs when the user touches the control.

Namespace: System.Windows.Controls.Primitives
Assembly: System.Windows (in System.Windows.dll)


Protected Overrides Sub OnMouseLeftButtonDown ( _
    e As MouseButtonEventArgs _
protected override void OnMouseLeftButtonDown(
    MouseButtonEventArgs e



Exception Condition

e is nullNothingnullptra null reference (Nothing in Visual Basic).


This method marks the MouseLeftButtonDown event as handled by setting the MouseButtonEventArgs..::.Handled property of the event data to true when the button is enabled and its ClickMode is not set to Hover. Since this method marks the MouseLeftButtonDown event as handled in some situations, you should use the Click event instead to detect a button click.

Notes to Inheritors

If you override OnMouseLeftButtonDown, always call the base implementation in your OnMouseLeftButtonDown implementation. Failure to call the base implementation prevents base classes from handling the event with a class handler, which might change the run-time behavior of the final class. You can call the base implementation either before or after your special handling, depending on your requirements.

Version Information

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0


Windows Phone

See Also


ButtonBase Class

System.Windows.Controls.Primitives Namespace