Question

I’m trying to retrieve the return value of a stored procedure in SQL Server 2005 as follows:

        OleDbCommand comm = new OleDbCommand(process_name, connection);
        comm.CommandType = CommandType.StoredProcedure;

        for (int i = 0; i < process_parameters.Length; i++)
            comm.Parameters.AddWithValue(process_parameters[i].ParameterName, process_parameters[i].Value);

        //Add output param
        comm.Parameters.Add("@TestID", OleDbType.Integer).Direction = ParameterDirection.ReturnValue;

        comm.ExecuteNonQuery();

When ExecuteNonQuery() is called, however, I get back a OleDbException saying: “Procedure or function myStoredProcedure has too many arguments specified.” My stored procedure begins as follows:

ALTER PROCEDURE [dbo].[spTabtempTestsINSERT]
(
            @Param1     char (64),
            @Param2     char (128),
            @Param3     char (64),
)
AS
BEGIN
    Declare     @TestID         int

And ends with the following:

    RETURN @TestID
END

Does the fact that the return value is declared, rather than being passed as a parameter, have anything to do with it? If so, how can I get the return value of a param that’s declared after the stored procedure begins? Thanks for your help.

UPDATE:
I’ve tried the changes suggested so far, I added the following line:

            OleDbCommand comm = new OleDbCommand(process_name, connection);
            comm.CommandType = CommandType.StoredProcedure;

            for (int i = 0; i < process_parameters.Length; i++)
                comm.Parameters.AddWithValue(process_parameters[i].ParameterName, process_parameters[i].Value);

            var testID = (int)comm.ExecuteScalar();

Now when ExecuteScalar() gets executed, I get a NullReferenceException with Object reference not set to an instance of an object.

Note: I also tried setting it to an integer int testID = (int)comm.ExecuteScalar(); and I still get the same error.

Answer 1

Ok, I was able to get it to work properly. My problem was that, I neglected to declare any of the parameters as OUTPUT, I added an extra variable and set that as the output variable and had the stored procedure return that. After word I just checked that output parameter ,after calling the stored procedure, from my C# code, the following shows the changes:

ALTER PROCEDURE [dbo].[spTabtempTestsINSERT]
(
            @Param1     char (64),
            @Param2     char (128),
            @Param3     char (64),
            @ReturnValue int OUTPUT
)
AS
BEGIN
    Declare     @TestID         int

And at the end make a simple change:

    SET @ReturnValue = @TestID
    RETURN @ReturnValue
END

Finally, back in my code:

        OleDbCommand comm = new OleDbCommand(process_name, connection);
        comm.CommandType = CommandType.StoredProcedure;

    for (int i = 0; i < process_parameters.Length; i++)
        comm.Parameters.AddWithValue(process_parameters[i].ParameterName, process_parameters[i].Value);

       //Add output param
        comm.Parameters.Add("@ReturnValue", OleDbType.Integer).Direction = ParameterDirection.ReturnValue;

        comm.ExecuteNonQuery();
        Console.WriteLine("Stored Procedure returned a value of "+ comm.Parameters["@ReturnValue"].Value); //Success

Thank you all for your suggestions. Any alternatives or further insights are welcome.