This documentation is archived and is not being maintained.

ComponentChangingEventHandler Delegate

Represents the method that will handle a ComponentChanging event.

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

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


Type: System.Object
The source of the event.
Type: System.ComponentModel.Design.ComponentChangingEventArgs
A ComponentChangingEventArgs event that contains the event data.

When you create a ComponentChangingEventHandler 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.

This example demonstrates registering a ComponentChangingEventHandler and handling the ComponentChanging event.

public void LinkComponentChangingEvent(IComponentChangeService changeService)
    // Registers an event handler for the ComponentChanging event.
    changeService.ComponentChanging += new ComponentChangingEventHandler(this.OnComponentChanging);            

private void OnComponentChanging(object sender, ComponentChangingEventArgs e)
    // Displays changing component information on the console.
    Console.WriteLine("Type of the component that is about to change: "+e.Component.GetType().FullName);      
    Console.WriteLine("Name of the member of the component that is about to change: "+e.Member.Name);                        

.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.