ado.net获取存储过程的返回值

--------------------------------------------
假设有存储过程如下:
---------------------------------------------

CREATE proc sp_uptmp @tmpName varchar(50),@srcPos varchar(255)
as
Begin TRAN
insert into t_template values(@tmpName,@srcPos)
COMMIT

return isnull(@@identity,0)
GO

------------------------------------------------------------
在 ado.net 里面获取返回值的方法为(c#):
------------------------------------------------------------
SqlConnection dbconn = new SqlConnection(connStr);
SqlCommand cmd = new SqlCommand("sp_uptmp",dbconn);
cmd.CommandType = CommandType.StoredProcedure; SqlParameter tmpName = cmd.Parameters.Add("@tmpName",SqlDbType.VarChar);
SqlParameter srcPos = _cmd.Parameters.Add("@srcPos",SqlDbType.VarChar);
SqlParameter rtnval = cmd.Parameters.Add("rval",SqlDbType.Int); tmpName.Direction = ParameterDirection.Input;
srcPos.Direction = ParameterDirection.Input;
rtnval.Direction = ParameterDirection.ReturnValue; tmpName.Value = "";
srcPos.Value = "";
dbconn.Open();
cmd.ExecuteNonQuery();
dbconn.Close(); tmpid = (int)rtnval.Value; //此处即为返回值