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LoginCancelEventArgs.Cancel Property

Gets or sets a value indicating whether the event should be canceled.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

public bool Cancel { get; set; }

Property Value

Type: System.Boolean
true if the event should be canceled; otherwise, false.

You can use the Cancel property to indicate whether an event, such as the LoggingIn event, the LoggingOut event, or the ChangingPassword event, should be canceled.

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 sets the Cancel property to true, and an error message is displayed. For an .aspx file that can be used to run the example, see the LoginCancelEventArgs topic.

public partial class LoginCancelEventArgscs_aspx : System.Web.UI.Page
{

    bool IsValidEmail(string strIn)
    {
        // Return true if strIn is in valid e-mail format. 
        return System.Text.RegularExpressions.Regex.IsMatch(strIn, 
            @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$");
    }

    protected void OnLoggingIn(object sender, System.Web.UI.WebControls.LoginCancelEventArgs e)
    {
        if (!IsValidEmail(Login1.UserName))
        {
            Login1.InstructionText = "You must enter a valid e-mail address.";
            e.Cancel = true;
        }
        else
        {
            Login1.InstructionText = String.Empty;
        }
    }
}

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0
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