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IComponentChangeService.OnComponentChanging Method

Announces to the component change service that a particular component is changing.

[Visual Basic]
Sub OnComponentChanging( _
   ByVal component As Object, _
   ByVal member As MemberDescriptor _
void OnComponentChanging(
   object component,
 MemberDescriptor member
void OnComponentChanging(
   Object* component,
 MemberDescriptor* member
function OnComponentChanging(
   component : Object,
 member : MemberDescriptor


The component that is about to change.
The member that is changing. This is a null reference (Nothing in Visual Basic) if this change is not related to a single member.


This method raises the ComponentChanging event.

Most designers included with the .NET Framework SDK, as well as the Visual Studio .NET design-time environment, typically raise this event automatically, so most of the time, you do not need to explicitly call this method. The appropriate IComponentChangeService events are automatically raised when a PropertyDescriptor is used to change a property value or components are added or removed from the IDesignerHost container.

Notes to Implementers:  This method throws an exception if the property cannot be changed. This is not intended to validate the values of a particular property. Instead, it is intended to provide a global method of preventing a component from changing. For example, if a designer file is checked into source code control, this event's handler would typically throw an exception if the user refused to check out the file.


Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

IComponentChangeService Interface | IComponentChangeService Members | System.ComponentModel.Design Namespace | MemberDescriptor

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