title: C# - Pl/SQL Problem with out parameter in stored procedure
body: <p>I have a stored procedure which looks like this:     </p>
  
  <pre><code>    PROCEDURE semifinished_lable_data(p_piece_num_id     IN INTEGER,
                                          p_piece_id         OUT STRING,
                                          p_tickness         OUT NUMBER)
     IS begin
      select p_piece_id,p_tickness into p_piece_id,p_tickness from piece p where p.piece_num_id=p_piece_num_id;
     end;
  </code></pre>
  
  <p>I've executed it from the database and it worked perfectly. When I execute it from c# app I don't get any value back.</p>
  
  <p>Then when I researched the problem , I added that : <strong>cmd.BindByName = true</strong> 
  But this time i got the following error</p>
  
  <blockquote>
    <p>multiple instances of named argument in list</p>
  </blockquote>
  
  <p>C# codes : </p>
  
  <pre><code> OracleCommand cmd = new OracleCommand();
              cmd.Connection = conn;
              cmd.InitialLONGFetchSize = 1000;
              var seciliProsedur = "QUA_PRINTING.semifinished_lable_data";
    cmd.CommandType = CommandType.StoredProcedure;
              cmd.CommandText = seciliProsedur;
              cmd.BindByName = true;
              object piece_num_id = gridViewMain.GetFocusedRowCellValue(gridViewMain.FocusedColumn);
   OracleParameter PAR_ID1 = new OracleParameter();
              PAR_ID1.ParameterName = "p_piece_id ";
              PAR_ID1.OracleDbType = OracleDbType.Int32;
              PAR_ID1.Direction = System.Data.ParameterDirection.Input;
              PAR_ID1.Value =piece_num_id;
              PAR_ID1.Size = 100;
              cmd.Parameters.Add(PAR_ID1);
  cmd.Parameters.Add("p_piece_id", OracleDbType.Varchar2, 1000, null, ParameterDirection.Output);
  cmd.Parameters.Add("p_tickness", OracleDbType.Double,200, null, ParameterDirection.Output);
  
   conn.Open();
  
  
              var da = new OracleDataAdapter(cmd);
              var dt = new DataTable();
              da.Fill(dt);
  </code></pre>
  
  <p>How can I solve this problem ?</p>