LoginCancelEventArgs Class
Assembly: System.Web (in system.web.dll)
A cancelable event is raised when a component is about to perform an action that can be canceled, such as logging on to a Web site.
The LoginCancelEventArgs class provides the Cancel property to indicate whether the event should be canceled. A LoginCancelEventArgs object is used with controls that have cancelable actions, such as the Login control, the CreateUserWizard control, and the PasswordRecovery control.
The following code example uses the LoggingIn event to ensure that the user has entered a well-formed e-mail address in the UserName property. If not, the LoggingIn event handler cancels the logon attempt by setting the Cancel property of the LoginCancelEventArgs object to true.Then the error message specified in the InstructionText property is displayed.
Partial Class LoginCancelEventArgsvb_aspx Inherits System.Web.UI.Page Function IsValidEmail(ByVal strIn As String) As Boolean ' Return true if strIn is in valid e-mail format. Return Regex.IsMatch(strIn, _ ("^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$")) End Function Protected Sub OnLoggingIn(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.LoginCancelEventArgs) If Not IsValidEmail(Login1.UserName) Then Login1.InstructionText = "You must enter a valid e-mail address." e.Cancel = True Else Login1.InstructionText = String.Empty End If End Sub End Class
The following is the .aspx file that can be used to run the preceding example.
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="LoginCancelEventArgs.vb" Inherits="LoginCancelEventArgsvb_aspx" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>ASP.NET Example</title> </head> <body> <form id="Form1" runat="server"> <asp:Login id="Login1" runat="server" onloggingin="OnLoggingIn"> </asp:Login> </form> </body> </html>
- AspNetHostingPermission for operating in a hosted environment. Demand value: LinkDemand; Permission value: Minimal.
- AspNetHostingPermission for operating in a hosted environment. Demand value: InheritanceDemand; Permission value: Minimal.
System.EventArgs
System.Web.UI.WebControls.LoginCancelEventArgs
System.Web.UI.WebControls.MailMessageEventArgs