webservice引用

  class VidyoPortalUserServiceWithAuthentication : VidyoPortalUserService
     {
         String _username;
         String _password;
         public VidyoPortalUserServiceWithAuthentication(String username, String password)
         {
             _username = username;
             _password = password;
         }
         protected override WebRequest GetWebRequest(Uri uri)
         {
             WebRequest wr = base.GetWebRequest(uri);
             wr.Headers.Add("Authorization", "Basic " +
                 Convert.ToBase64String(Encoding.ASCII.GetBytes(_username + ":" + _password)));
             return wr;
         }
     }

 VidyoPortalUserServiceWithAuthentication vpus = new VidyoPortalUserServiceWithAuthentication(this.tbxID.Text, this.tbxPwd.Text);

                 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(RequestString);

                 request.AllowAutoRedirect = false;
                 request.Method = "GET";
                 // Get Found (302) response.
                 HttpWebResponse response = (HttpWebResponse)request.GetResponse();