I have a customer setup that uses stored procedures to return data from its SQL Server database.
Those stored procedures are all built the same way - they take a bunch of input parameters, and they return:
the first is just a single row, single column with the result code (type INT
) - 0 for success, some other values otherwise; if the value is 0, then there's a second result set that contains the actual data
the second result set can be anything - any number of columns and rows
I'm trying to create a "generic" way to interface with this system, and my attempt is this:
- create a class that takes stored procedure name and input parameters
- a return type that contains both an
ErrorCode INT
property as well as a DataTable results
property
However, I'm having trouble getting this to work with ADO.NET and SQL Server 2008 R2.
My code boils down to this:
public MyResultType CallService(string procedureName, MyParameters parameters)
{
MyResultType result = new MyResultType { ErrorCode = 0 };
using (SqlConnection conn = new SqlConnection(_connectionString))
using (SqlCommand cmd = new SqlCommand(procedureName, conn))
{
cmd.CommandType = CommandType.StoredProcedure;
SetupParameters(cmd, parameters);
// open connection, execute the stored procedure
conn.Open();
using (SqlDataReader rdr = cmd.ExecuteReader())
{
// get the first result set - the status code, one row, one column of type INT
while (rdr.Read())
{
result.ErrorCode = rdr.GetInt32(0);
}
// if we got a "0" (success) -> go to the next result set and load it into the table
if(result.ErrorCode == 0 && rdr.NextResult())
{
result.ResultTable = new DataTable();
result.ResultTable.Load(rdr);
int colCount = result.ResultTable.Columns.Count;
int rowCount = result.ResultTable.Rows.Count;
}
rdr.Close();
}
conn.Close();
}
return result;
}
My issue is: the call to the stored procedure works just fine, the error code = 0 is picked up just fine, the data table is created and the number of columns is the expected value - but there are NO ROWS loaded...
I've been trying everything I can think of to get those rows into the DataTable - no luck. And of course - if I execute this very same stored procedure in SQL Server Management Studio, everything works just fine, I get my ErrorCode=0 and my result set of 18 columns and 5 rows - no problem....
What am I missing? Can anyone spot the problem in my code? Why aren't the rows of the second result set loaded (but the columns are being detected, it seems)?