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FormsAuthentication.RedirectToLoginPage Method (String)

Redirects the browser to the login URL with the specified query string.

Namespace: System.Web.Security
Assembly: System.Web (in system.web.dll)

public static void RedirectToLoginPage (
	string extraQueryString
)
public static void RedirectToLoginPage (
	String extraQueryString
)
public static function RedirectToLoginPage (
	extraQueryString : String
)
Not applicable.

Parameters

extraQueryString

The query string to include with the redirect URL.

The RedirectToLoginPage method redirects the browser to the LoginUrl and includes the extraQueryString value as the QueryString for the redirected URL.

The RedirectToLoginPage method does not clear the forms-authentication cookie. You can use the RedirectToLoginPage method in conjunction with the SignOut method to log one user out and allow a different user to log in.

The following code example clears the forms-authentication cookie using the SignOut method and redirects the user to the login page using the RedirectToLoginPage method.

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Web.Security" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

public void LoginLink_OnClick(object sender, EventArgs args)
{
  FormsAuthentication.SignOut();
  FormsAuthentication.RedirectToLoginPage(GetQueryString());
}

private string GetQueryString()
{
  string queryString = "";

  NameValueCollection qs = Request.QueryString;

  foreach (string key in qs.AllKeys)
    foreach (string value in qs.GetValues(key))
      queryString += Server.UrlEncode(key) + "=" + Server.UrlEncode(value) + "&";

  return queryString.TrimEnd('&');    
}

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
Welcome <b><%=User.Identity.Name%></b>. Not <b><%=User.Identity.Name%></b>? 
Click <asp:LinkButton id="LoginLink" Text="here" 
                      OnClick="LoginLink_OnClick" runat="server" />
to sign in.

<!-- Page Contents -->

</form>



</body>
</html>

Windows 98, Windows Server 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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