asp.net中IDataParameter调用存储过程的实现方法

public string GenerateExamePaper(string paperType, string driverID, string MacAddr)
{
  int i;
  IDataParameter[] iData = new SqlParameter[4];
  iData[0] = new SqlParameter("@paperType", paperType);
  iData[1] = new SqlParameter("@driverID", driverID);
  iData[2] = new SqlParameter("@MacAddr", MacAddr);
  iData[3] = new SqlParameter("@sReturn", SqlDbType.Char, 50, ParameterDirection.Output, false, 0, 0, string.Empty, DataRowVersion.Default,null);
  string aaa = "";
  i= DbHelperSQL.RunProcedureParOut("Pro_GenerateExamePaper", iData, out aaa).ToString();

  return aaa;
}

/// summary>
/// 执行存储过程，返回影响的行数 
/// /summary>
/// param name="storedProcName">存储过程名/param>
/// param name="parameters">存储过程参数/param>
/// param name="rowsAffected">影响的行数/param>

/// param name="rowsAffected">返回output值/param>

/// returns>/returns>
public static int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected,out str)
{
  using (SqlConnection connection = new SqlConnection(connectionString))
  {
 int result;
 connection.Open();
 SqlCommand command = BuildIntCommand(connection, storedProcName, parameters);
 rowsAffected = command.ExecuteNonQuery();
 result = (int)command.Parameters["ReturnValue"].Value;
    str= (int)command.Parameters["@sReturn"].Value;
 return result;
  }
}