Using the Login server control on the Login.aspx page (C#) : Login « Authentication Authorization « ASP.NET Tutorial

<%@ Page Language="C#" %>

<script runat="server">
    protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
    {
        if (Login1.UserName == "A" && Login1.Password == "B") {
            FormsAuthentication.RedirectFromLoginPage(Login1.UserName,
               Login1.RememberMeSet);
        }
        else {
            Response.Write("Invalid credentials");
        }
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Login Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Login ID="Login1" runat="server" OnAuthenticate="Login1_Authenticate">
        </asp:Login>
    </div>
    </form>
</body>
</html>

21.3.Login
	21.3.1.	Using a Template with the Login Control
	21.3.2.	Performing Custom Authentication with the Login Control
	21.3.3.	Automatically Redirecting a User to the Referring Page
	21.3.4.	Using the Login server control on the Login.aspx page (C#)
	21.3.5.	Using the Login server control on the Login.aspx page (VB)