1        public static DataTable ConvertDataReaderToDataTable(IDataReader reader)
 2        {
 3            DataTable objDataTable = new DataTable();
 4            int intFieldCount = reader.FieldCount;
 5            for (int intCounter = 0; intCounter < intFieldCount; ++intCounter)
 6            {
 7                objDataTable.Columns.Add(reader.GetName(intCounter), reader.GetFieldType(intCounter));
 8            }
 9
10            objDataTable.BeginLoadData();
11
12            object[] objValues = new object[intFieldCount];
13            while (reader.Read())
14            {
15                reader.GetValues(objValues);
16                objDataTable.LoadDataRow(objValues, true);
17            }
18            reader.Close();
19            objDataTable.EndLoadData() ;
20
21            return objDataTable;
22        }

From:http://didasoft.cnblogs.com/archive/2006/01/04/310846.html