ObjectType

using System.Collections.Generic;

using NUnit.Framework;

using BLToolkit.DataAccess;

namespace HowTo.DataAccess
{
    [TestFixture]
    public class ActualType
    {
        public interface IName
        {
            string Name { get; }
        }

        public class NameBase : IName
        {
            private string _name;
            public  string  Name { get { return _name; } set { _name = value; } }
        }

        public class Name1 : NameBase {}
        public class Name2 : NameBase {}

        [ActualType(typeof(IName), typeof(Name1))]
        public abstract class TestAccessor : DataAccessor
        {
            [SqlQuery("SELECT 'John' as Name")]
            public abstract IName GetName1();

            [SqlQuery("SELECT 'John' as Name"), ObjectType(typeof(Name2))]
            public abstract IName GetName2();

            [SqlQuery("SELECT 'John' as Name")]
            public abstract IList<IName> GetName1List();

            [SqlQuery("SELECT 'John' as Name"), ObjectType(typeof(Name2))]
            public abstract IList<IName> GetName2List();

            [SqlQuery("SELECT 1 as ID, 'John' as Name"), Index("@ID")]
            public abstract IDictionary<int, IName> GetName1Dictionary();

            [SqlQuery("SELECT 1 as ID, 'John' as Name"), Index("@ID"), ObjectType(typeof(Name2))]
            public abstract IDictionary<int, IName> GetName2Dictionary();
        }

        [Test]
        public void Test()
        {
            TestAccessor ta = DataAccessor.CreateInstance<TestAccessor>();

            Assert.IsTrue(ta.GetName1()              is Name1);
            Assert.IsTrue(ta.GetName2()              is Name2);
            Assert.IsTrue(ta.GetName1List()[0]       is Name1);
            Assert.IsTrue(ta.GetName2List()[0]       is Name2);
            Assert.IsTrue(ta.GetName1Dictionary()[1] is Name1);
            Assert.IsTrue(ta.GetName2Dictionary()[1] is Name2);
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <appSettings>
        <add
            key   = "ConnectionString"
            value = "Server=.;Database=BLToolkitData;Integrated Security=SSPI"/>
    </appSettings>
</configuration>