Cool ASP.NET 'trick' I've been working on..
Im  taking a DataReader and slammin' it into a DataTable, but the idea is that I want to cache the DataTable in the Page Cache object, and create
DataViews of the data in the table for paging and sorting purposes.

This way I get a quick forward-only DataReader on the Page Load, with sorting and paging capabilities, in a biz-tier
data object, and the class is reusable for other biz-tier objects.  (I have thousands of records in the database, so less time loading, and less round-tripping for paging/sorting, is essential.)

In order to do this, I wanted to have some recordID's for the paging, and in order to ensure we never clash with another PrimaryKey from the underlying
database (DataReader pull) I went with negative numbers. So I created an autoincrement column, filled the DataTable with the DataReader Schema first,
added the autoinc column, THEN fill the DataTable so I don't lose the autoincrement column.

The DataTable will now get returned to the caller, where I will slam it into the cache and create views, etc. off of it.  Sweet :)

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Text;

namespace payc_bl
{
    /// <summary>
    /// Utilizes generic DBDataAdapter to return DataTables from DataReaders
    /// </summary>
    class PAYCDataTable : DbDataAdapter
    {

        public int FillFromReader(DataTable dataTable, IDataReader dataReader)
        {
            // Create a DataColumn and set various properties.
            DataColumn myColumn = new DataColumn("recordID");
            myColumn.DataType = System.Type.GetType("System.Int32");
            myColumn.AutoIncrement = true;
            myColumn.AutoIncrementSeed = -1;
            myColumn.AutoIncrementStep = -1;
           
            // Fill the DataTable with Schema, add the column, and set its Primary Key
            dataTable = this.FillSchema(dataTable, SchemaType.Mapped, dataReader);
            dataTable.Columns.Add(myColumn);
            DataColumn[] keys = new DataColumn[1];
            keys[0] = myColumn;
            dataTable.PrimaryKey = keys;
           
            // Fill the DataTable with the DataReader data
            return this.Fill(dataTable, dataReader);
        }

        protected override RowUpdatedEventArgs CreateRowUpdatedEvent(
        DataRow dataRow,
        IDbCommand command,
        StatementType statementType,
        DataTableMapping tableMapping
        ) { return null; }

        protected override RowUpdatingEventArgs CreateRowUpdatingEvent(
        DataRow dataRow,
        IDbCommand command,
        StatementType statementType,
        DataTableMapping tableMapping
        ) { return null; }

        protected override void OnRowUpdated(
        RowUpdatedEventArgs value
        ) { }

        protected override void OnRowUpdating(
        RowUpdatingEventArgs value
        ) { }
    }
}