bool GenerateSecurityToken()
        {
            if (securityToken != string.Empty)
            {
                return(true);
            }

            securityToken = string.Empty;
            Uri uri = new Uri("GenerateSecurityToken", UriKind.Relative);

            DataServiceRequest <string> loginRequest = new DataServiceRequest <string>(uri);
            var loginResponse = sldDataServiceContext.ExecuteBatch(loginRequest);
            QueryOperationResponse <string> queryOperationResponse = loginResponse.FirstOrDefault() as QueryOperationResponse <string>;

            if (queryOperationResponse == null)
            {
                return(false);
            }

            string token = queryOperationResponse.FirstOrDefault();

            if (token == null)
            {
                return(false);
            }

            securityToken = token;

            return(true);
        }