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ActiveDesignerEventHandler Delegate

Represents the method that will handle the ActiveDesignerChanged event.

Namespace:  System.ComponentModel.Design
Assembly:  System (in System.dll)

[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public delegate void ActiveDesignerEventHandler(
	Object sender,
	ActiveDesignerEventArgs e


Type: System.Object
The source of the event.
Type: System.ComponentModel.Design.ActiveDesignerEventArgs
An ActiveDesignerEventArgs that contains the event data.

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 Events and Delegates.


The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

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 += 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);

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Community Additions

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