GetUserDetails

public static string GetUserDetails(string stringInput, int displayoption)
          {
                if (stringInput == "")
                {
                    return strErrorMessage_GetUserDetails;
                }
                else
                {
                    string strUserName = "";
                    string strName = "";
                    string strReturnString = "";

                    string query1 = "SELECT user_name, first_name, last_name FROM users where user_id = '" + stringInput + "'";
                    //    strReturnString = "<p>" + query1 + "</p>";

                    using (SqlConnection conn1 = new SqlConnection(connString))
                    {
                        using (SqlCommand cmd1 = new SqlCommand(query1, conn1))
                        {
                            conn1.Open();
                            SqlDataReader rdr1 = cmd1.ExecuteReader();
                            if (rdr1.HasRows)
                            {
                                while (rdr1.Read())
                                {
                                    strUserName = rdr1["user_name"].ToString();
                                    strName = rdr1["first_name"].ToString() + " " + rdr1["last_name"].ToString();

                                    switch (displayoption)
                                    {
                                        case 1:
                                            strReturnString = strReturnString + strUserName;
                                            break;
                                        case 2:
                                            strReturnString = strReturnString + strName + " (" + strUserName + ")";
                                            break;
                                        default:
                                            strReturnString = strReturnString + strName + " (" + strUserName + " " + stringInput + ")";
                                            break;
                                    }
                                }
                            }
                        }
                    }
                    return strReturnString;
                }