RoutedCommand.Execute(Object, IInputElement) Method

Definition

Namespace:

System.Windows.Input

Assembly:

PresentationCore.dll

Executes the RoutedCommand on the current command target.

public:
 void Execute(System::Object ^ parameter, System::Windows::IInputElement ^ target);

public void Execute (object parameter, System.Windows.IInputElement target);

member this.Execute : obj * System.Windows.IInputElement -> unit

Public Sub Execute (parameter As Object, target As IInputElement)

Parameters

parameter

Object

User defined parameter to be passed to the handler.

target

IInputElement

Element at which to begin looking for command handlers.

Exceptions

InvalidOperationException

target is not a UIElement or ContentElement.

Examples

The following example is from a custom implementation of ICommandSource sample.

this.Command in this example is the Command property on the ICommandSource. If the command is not null, the command is cast to a RoutedCommand. If it is a RoutedCommand, then the Execute method is called passing the CommandTarget and the CommandParameter. If the command is not a RoutedCommand, it is cast to an ICommand and the Execute method is called passing the CommandParameter.

// If Command is defined, moving the slider will invoke the command;
// Otherwise, the slider will behave normally.
protected override void OnValueChanged(double oldValue, double newValue)
{
    base.OnValueChanged(oldValue, newValue);

    if (this.Command != null)
    {
        RoutedCommand command = Command as RoutedCommand;

        if (command != null)
        {
            command.Execute(CommandParameter, CommandTarget);
        }
        else
        {
            ((ICommand)Command).Execute(CommandParameter);
        }
    }
}

' If Command is defined, moving the slider will invoke the command;
' Otherwise, the slider will behave normally.
Protected Overrides Sub OnValueChanged(ByVal oldValue As Double, ByVal newValue As Double)
    MyBase.OnValueChanged(oldValue, newValue)

    If Me.Command IsNot Nothing Then
        Dim command As RoutedCommand = TryCast(Me.Command, RoutedCommand)

        If command IsNot Nothing Then
            command.Execute(CommandParameter, CommandTarget)
        Else
            CType(Me.Command, ICommand).Execute(CommandParameter)
        End If
    End If
End Sub

Remarks

The actual logic that executes the RoutedCommand is not contained in the Execute methods. Execute raises the PreviewExecuted and Executed events, which tunnel and bubble through the element tree looking for an object with a CommandBinding. If a CommandBinding for that RoutedCommand is found, then the ExecutedRoutedEventHandler attached to CommandBinding is called. These handlers supply the programming logic that performs the RoutedCommand.

The PreviewExecuted and Executed events are raised on the CommandTarget. If the CommandTarget is not set on the ICommandSource, the PreviewExecuted and Executed events are raised on the element with keyboard focus.