Using datareader instead of dataset

Hi I am Using a dataset to return data but want to convert this to
datareader but can't find much doumentation can anyone help me here is
my current code


iDB2Connection connDB2=new iDB2Connection(
  "DataSource=TDC01;" +
  "userid=RDS;password=sootarsing;DefaultCollection=QGPL;");
DataSet ds = new DataSet();
iDB2DataAdapter adpt = new iDB2DataAdapter();
string szSQLstmt = "Select * from ctx4nthg where REF ='" +@filter+"'";
adpt.SelectCommand = new iDB2Command(szSQLstmt,connDB2);
adpt.Fill(ds);
return ds;

______________________________________________________________________________
This message has been checked for viruses by Corpex
using the ArmourPlate Virus Scanning Service. To find out
how to protect your company visit http://www.armourplate.com
or call Corpex on +44 (0)207 430 8000.