C#调用plsql存储过程返回带游标类型，总是返回不了结果集，为空，哪里有误呢？

Question

string connstl = "Data Source=TTT;User Id=123;Password=123";
            OracleConnection Con = new OracleConnection(connstl);
            Con.Open();
            OracleCommand Cmd = new OracleCommand("DGA1180NC.P_SREFER", Con);
            Cmd.CommandType = CommandType.StoredProcedure;
            OracleParameter p1 = new OracleParameter(txt_prc_line.Text, OracleDbType.Varchar2);
            p1.Direction = ParameterDirection.Input;
            OracleParameter p2 = new OracleParameter(datefr, OracleDbType.Varchar2);
            p2.Direction = ParameterDirection.Input;
            OracleParameter p3 = new OracleParameter(dateto, OracleDbType.Varchar2);
            p3.Direction = ParameterDirection.Input;
            OracleParameter p4 = new OracleParameter("P_CUR", OracleDbType.RefCursor);
            p4.Direction = ParameterDirection.Output;
            Cmd.Parameters.Add(p1);
            Cmd.Parameters.Add(p2);
            Cmd.Parameters.Add(p3);
            Cmd.Parameters.Add(p4);            DataSet ds = new DataSet();
            OracleDataAdapter da = new OracleDataAdapter(Cmd);
            da.Fill(ds);            DataTable dt = ds.Tables["P_CUR"];
            Con.Close();

Answer 1

调试运行 
OracleDataAdapter da = new OracleDataAdapter(Cmd);有返回值么？你的存储过程对么？