ActiveDesignerEventHandler Delegate

Reference

Definition

Namespace:: System.ComponentModel.Design

Assemblies:: netstandard.dll, System.ComponentModel.TypeConverter.dll

Assembly:: System.ComponentModel.TypeConverter.dll

Assembly:: System.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Represents the method that will handle the ActiveDesignerChanged event.

public delegate void ActiveDesignerEventHandler(System::Object ^ sender, ActiveDesignerEventArgs ^ e);

public delegate void ActiveDesignerEventHandler(object sender, ActiveDesignerEventArgs e);

public delegate void ActiveDesignerEventHandler(object? sender, ActiveDesignerEventArgs e);

type ActiveDesignerEventHandler = delegate of obj * ActiveDesignerEventArgs -> unit

Public Delegate Sub ActiveDesignerEventHandler(sender As Object, e As ActiveDesignerEventArgs)

Parameters

sender: Object

The source of the event.

e: ActiveDesignerEventArgs

An ActiveDesignerEventArgs that contains the event data.

Examples

The following example demonstrates registering an ActiveDesignerEventHandler and handling an ActiveDesignerChanged event.

public:
   void LinkActiveDesignerEvent( IDesignerEventService^ eventService )
   {
      // Registers an event handler for the ActiveDesignerChanged event.
      eventService->ActiveDesignerChanged += gcnew ActiveDesignerEventHandler( this, &MiscCompModSamples::ActiveDesignerEventHandlerExample::OnActiveDesignerEvent );
   }

private:
   void OnActiveDesignerEvent( Object^ /*sender*/, ActiveDesignerEventArgs^ e )
   {
      // Displays changed designer information on the console.
      if ( e->NewDesigner->RootComponent->Site != nullptr )
      {
         Console::WriteLine( "Name of the component of the new active designer: {0}", e->NewDesigner->RootComponent->Site->Name );
      }
      Console::WriteLine( "Type of the component of the new active designer: {0}", e->NewDesigner->RootComponentClassName );
      if ( e->OldDesigner->RootComponent->Site != nullptr )
      {
         Console::WriteLine( "Name of the component of the previously active designer: {0}", e->OldDesigner->RootComponent->Site->Name );
      }
      Console::WriteLine( "Type of the component of the previously active designer: {0}", e->OldDesigner->RootComponentClassName );
   }

public void LinkActiveDesignerEvent(IDesignerEventService eventService)
{
    // Registers an event handler for the ActiveDesignerChanged event.
    eventService.ActiveDesignerChanged += new ActiveDesignerEventHandler(this.OnActiveDesignerEvent);
}

private void OnActiveDesignerEvent(object sender, ActiveDesignerEventArgs e)
{
    // Displays changed designer information on the console.
    if( e.NewDesigner.RootComponent.Site != null )
        Console.WriteLine("Name of the component of the new active designer: "+e.NewDesigner.RootComponent.Site.Name);
    Console.WriteLine("Type of the component of the new active designer: "+e.NewDesigner.RootComponentClassName);
    if( e.OldDesigner.RootComponent.Site != null )
        Console.WriteLine("Name of the component of the previously active designer: "+e.OldDesigner.RootComponent.Site.Name);
    Console.WriteLine("Type of the component of the previously active designer: "+e.OldDesigner.RootComponentClassName);
}

Public Sub LinkActiveDesignerEvent(ByVal eventService As IDesignerEventService)
    ' Registers an event handler for the ActiveDesignerChanged event.
    AddHandler eventService.ActiveDesignerChanged, AddressOf Me.OnActiveDesignerEvent
End Sub

Private Sub OnActiveDesignerEvent(ByVal sender As Object, ByVal e As ActiveDesignerEventArgs)
    ' Displays changed designer information on the console.            
    If (e.NewDesigner.RootComponent.Site IsNot Nothing) Then
        Console.WriteLine(("Name of the component of the new active designer: " + e.NewDesigner.RootComponent.Site.Name))
    End If
    Console.WriteLine(("Type of the component of the new active designer: " + e.NewDesigner.RootComponentClassName))
    If (e.OldDesigner.RootComponent.Site IsNot Nothing) Then
        Console.WriteLine(("Name of the component of the previously active designer: " + e.OldDesigner.RootComponent.Site.Name))
    End If
    Console.WriteLine(("Type of the component of the previously active designer: " + e.OldDesigner.RootComponentClassName))
End Sub

Remarks

The ActiveDesignerChanged event is raised when the currently active document has been modified.

When you create an ActiveDesignerEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Handling and Raising Events.

Extension Methods

GetMethodInfo(Delegate)

Gets an object that represents the method represented by the specified delegate.

Applies to

Product	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

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