protected void Sub_Click(   object sender, EventArgs e)

        {            

            if (TextBox_Name.Text == string.Empty || TextBox_Pwd.Text == string.Empty)

            {

                Response.Write("<script>alert('You don't enter username or password, please input it!');</script>");

                return;

            }



            string ldapPath = "LDAP://" + GetDomainName();

            string domainAndUsername = Environment.UserDomainName + "\\" + TextBox_Name.Text;

            DirectoryEntry entry = new DirectoryEntry(ldapPath, domainAndUsername,    TextBox_Pwd.Text);



            DirectorySearcher search = new DirectorySearcher(entry);



            try

            {

                SearchResult result = search.FindOne();               

         //       Response.Write("<script>alert('login successful');</script>");

                Session["UserID"] = TextBox_Name.Text.Trim();              

                Response.Redirect("index.aspx");



            }

            catch (Exception ex)

            {