Occurs when a user submits login information, before authentication takes place.
Assembly: System.Web (in System.Web.dll)
The event is raised when a user submits login information but before the user is authenticated on the Web site. Use the event to set up any information that you need before authenticating a user.
For more information about handling events, see Handling and Raising Events.
The following code example uses the event to ensure that the user has entered a well-formed e-mail address in the UserName property. If not, the event cancels the login attempt and displays an error message using the InstructionText property.
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.