How to return oracle output parameters from a stored procedure in .NET

It seems you cannot use existing variable as output parameter, try this way instead

ora_cmd.Parameters.Add("Lc_Exito", OracleDbType.Int32).Direction = ParameterDirection.Output;ora_cmd.ExecuteNonQuery();if (ora_cmd.Parameters["Lc_Exito"].value == 0)

I have not found anywhere where it documents the whole process in one place, so after hitting my head against the wall and banging it out, here is my version of what I came up with, using one of the output parameters from the OP's code:

OracleParameter param = new OracleParameter();param = ora_cmd.Parameters.Add("Lc_Exito", OracleDbType.Int32, ParameterDirection.Output);  // can assign the direction within the parameter declarationparam.Size = 25;  // failed for me if I did not have this - should be the same as the DB field, if exporting a value from the databaseora_cmd.ExecuteNonQuery();int myLc_ExitoValue = int.Parse(param.Value);  // might not need to parse, and might need a .ToString() on param.Value if you do - I was using strings so not sure about OP's exact case

Then the stored procedure needs to be set up to accept the OUT parameter and you must assign to it in the procedure:

create or replace procedure PR_ABC_P_ALTA_TARJETA_PAYWARE(Lc_Exito OUT number)  as  begin    Lc_Exito := 123;  end; /

Obviously this leaves out all the other parameters that were being sent in and the other "out" parameters - wanted to simplify it. But this shows how everything gets set up, from before, during, and after the call to the stored procedure in the C#, and how to set the OUT parameter, and get the value out, of the stored procedure.