Hi everybody

I have a Stored procedure(SyBase 12.5) that returns a OUTPUT value, but it always returns a DBNull. I test the SP in other application (DBArtisan like a Query Analizer) and it returns the correct value, but when I test in my NET application (made in C#) it returns DBNull. If I try to make a cast I get the exception "Object cannot be cast from DBNull to other types"

This is my code my SP:

CREATE PROCEDURE dbo.sp_Prueba(
                 @vsTransId char(4),
                 @vsContratoId varchar(4),
          @vsLoginUser varchar(40),
         @vsParamList varchar(200),
         @iResp int OUTPUT
                              )
AS
    Declare @iError int
    Declare @OK int

    BEGIN

       Select @iError = 0
       Select @OK = 0

       BEGIN TRAN Pruebas

        Insert into LogTransacc
            Values (@vsTransId,@vsContratoId,@vsLoginUser,"Pruebas Juan",@vsParamList,"Ini",getdate())

            Select @iError = @@error

        if(@iError = @OK)
        Begin
          Select @iResp = @OK
          COMMIT TRAN Pruebas
        End
        else
        Begin
          Select @iResp = @iError
          ROLLBACK TRAN Pruebas
        End

    END

And this my function:

    private void Insertar() {
        string strcadena = cadenaConn;
        OleDbConnection oleConn = null;
        try {
            oleConn = new OleDbConnection(strcadena);
            oleConn.Open();

            OleDbCommand oleCmmd = new OleDbCommand();

            oleCmmd.CommandType = CommandType.StoredProcedure;
            oleCmmd.Connection = oleConn;
            oleCmmd.CommandText = "sp_Prueba";

            oleCmmd.Parameters.Add("@vsTransId",OleDbType.Char ,4);
            oleCmmd.Parameters["@vsTransId"].Value = "9500";

            oleCmmd.Parameters.Add("@vsContratoId",OleDbType.V arChar,4);
            oleCmmd.Parameters["@vsContratoId"].Value = "0000";

            oleCmmd.Parameters.Add("@vsLoginUser",OleDbType.Va rChar,40);
            oleCmmd.Parameters["@vsLoginUser"].Value = "Juan Carlos Gonzalez";

            oleCmmd.Parameters.Add("@vsParamList",OleDbType.Va rChar,200);
            oleCmmd.Parameters["@vsParamList"].Value = "Esta es una prueba para insertar utilizando Threads";

            oleCmmd.Parameters.Add("@iResp", OleDbType.Integer);
            oleCmmd.Parameters["@iResp"].Direction = ParameterDirection.Output;

            oleCmmd.ExecuteNonQuery();

            if(oleCmmd.Parameters["@iResp"].Value.Equals(System.DBNull.Value))
                 MessageBox.Show("OUTPUT Null");

                        else
                             MessageBox.Show("OUTPUT Not null");

            oleCmmd.Dispose();

        }
        catch(Exception Ex) {
            Console.WriteLine(Ex.Message);
        }
        finally {
            if(oleConn != null) {
                if(oleConn.State != System.Data.ConnectionState.Closed)
                    oleConn.Close();
            }
        }
}

Does someone help me, please?

Regards
J.C.