Assembly: System.Web (in System.Web.dll)
The WebPartAdding event is raised by the OnWebPartAdding method just before adding a control to a Web Parts zone. This event provides an opportunity to cancel the process before it is complete. The WebPartAdded event is called after a control has been added to a Web Parts zone.
The method specified in the delegate is called when a WebPartAdding event is raised.
Page developers can provide custom handlers for the event by adding the OnWebPartAdding attribute to the <asp:webpartmanager> element in a page, and assigning a custom method name to the attribute. A custom handler can also be assigned programmatically. For more information on programmatically assigning an event handler, see How to: Connect Event Handler Methods to Events.
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.