to check for administrator

[colrated]

I have developed a web application and only the user that has the administrator role can access it and no one else..I am having difficulty trying to figure out if the user is administrator or not////My code for login page is\[code\]public partial class LoginPage : System.Web.UI.Page{ public const int LOGON32_LOGON_INTERACTIVE = 2; public const int LOGON32_PROVIDER_DEFAULT = 0; //WindowsImpersonationContext impersonationContext; [DllImport("advapi32.dll")] public static extern int LogonUserA(String lpszUserName, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken); [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern int DuplicateToken(IntPtr hToken, int impersonationLevel, ref IntPtr hNewToken); [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern bool RevertToSelf(); [DllImport("kernel32.dll", CharSet = CharSet.Auto)] public static extern bool CloseHandle(IntPtr handle); protected void LoginButton_Click(object sender, EventArgs e) { IntPtr token = IntPtr.Zero; IntPtr tokenDuplicate = IntPtr.Zero; if(LogonUserA(UserName.Text, Domain.Text, Password.Text, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, ref token) != 0) { System.Security.Principal.WindowsIdentity wi = System.Security.Principal.WindowsIdentity.GetCurrent(); System.Security.Principal.WindowsPrincipal wp = new System.Security.Principal.WindowsPrincipal(wi); if (wp.IsInRole("Administrators")) { BadCredentials.Visible = false; Session["userName"] = UserName.Text; Session["password"] = Password.Text; Session["domain"] = Domain.Text; FormsAuthentication.RedirectFromLoginPage(UserName.Text, false); } else { BadCredentials.Visible = true; Label1.Text = wp.Identity.ToString(); Label2.Text = wi.Name.ToString(); Label3.Text = "not Admin"; } } else { BadCredentials.Visible = true; Label4.Text = "not valid user"; }\[/code\]When i put Administrator and the passwordIn this the Label2.text gives me \[quote\] XYZCOMP\IUSR_XYZCOMP\[/quote\]and does not go to the next page....any help please... thanksI am using forms authentication\[code\]> <authentication mode="Forms"> <forms> name="AuthCookie"> LoginUrl="Login.aspx" timeout = "60"> /> </authentication> <authorization>> <deny users="?" /> > <allow users="*" />> </authorization>\[/code\]