Linq2ADO

DataReaderExtensions.cs

namespace ACV.Common.DB
{
    using System;
    using System.Collections.Generic;
    using System.Data;
    using System.Data.Common;

    public static class SqlExtensions
    {
        private static object GetOrDefault(this IDataRecord record, string columnName, object @default = null)
        {
            var value = record[columnName];
            return value == null || value is DBNull ? @default : value;
        }

        public static T GetOrDefault<T>(this IDataRecord record, string columnName, T @default = default(T))
        {
            var value = GetOrDefault(record, columnName, (object)@default);
            return (T)Convert.ChangeType(value, typeof(T));
        }

        public static T ParseOrDefault<T>(this IDataRecord record, string columnName, Func<string, T> convertFunc, T @default = default(T))
        {
            var value = GetOrDefault(record, columnName, (object)@default);
            if (value is T) return (T)value;

            return value == null ? @default : convertFunc.Invoke(value.ToString());
        }

        public static IEnumerable<IDataRecord> ToEnumerable(this DbDataReader reader)
        {
            for (var enumerator = reader.GetEnumerator(); enumerator.MoveNext();)
            {
                yield return (IDataRecord)enumerator.Current;
            }
        }
    }
}

SampleClient.cs

namespace ACV.SampleClient
{
  using System.Collections.Generic;
  using System.Data;
  using System.Data.SqlClient;

  using ACV.Common.DB;

public class Client
  {
    public IList<Currency> GetCurrenciesByCode(string code)
    {
      code = NormalizeStringCode(code);

      using (var connection = OpenConnection())
      using (var command = CreateSpCommand(connection, code))
      using (var reader = command.ExecuteReader(CommandBehavior.SequentialAccess))
      {
        return reader.ToEnumerable()
          .Select(RecordToEntry)
          .Where(entry => entry.VariationRate != null)
          .ToList();
      }
    }

    private static Currency RecordToEntry(IDataRecord record)
    {
      return new Currency(
        record.GetOrDefault("Code", string.Empty).Trim(),
        record.GetOrDefault("Name", string.Empty).Trim(),
        record.GetOrDefault("DecimalPlaces", 0),
        record.GetOrDefault<int?>("VariationRate"));
    }
  }

  ...
}