How do I get AutoMapper to not cache mapped objects?

Question

When AutoMapper encounters an object that\'s already been mapped, it seems to use that object again, instead of trying to re-map it. I believe it does this based on .Equal

Answer 1

When AutoMapper encounters an object that's already been mapped, it seems to use that object again, instead of trying to re-map it. I believe it does this based on .Equals()

Can you explain why and when you see that ?

After a quick look in the source code, I'm sure there is no cache for objects. Here is a test that illustrate this :

   public class CustomerSource
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public DateTime DateOfBirth { get; set; }

        public int NumberOfOrders { get; set; }
    }

    public class CustomerTarget
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public DateTime DateOfBirth { get; set; }

        public int NumberOfOrders { get; set; }
    }

    [TestMethod]
    public void Test_AutoMapper()
    {
        Mapper.CreateMap();

        var source = new CustomerSource() { DateOfBirth = DateTime.Now, FirstName = "FirstName", LastName = "LastName", NumberOfOrders = int.MaxValue };

        var res1 = Mapper.Map(source);
        Console.WriteLine(res1.FirstName); // PRINT FirstName

        source.FirstName += "[UPDATED]";
        source.LastName += "[UPDATED]";

        var res2 = Mapper.Map(source);
        Console.WriteLine(res1.FirstName); // PRINT FirstName[UPDATED]

    }

Without your code, it is difficult to go more deeply. There is also a method Mapper.Reset() that clears the MapperEngine and the MapingConfiguration (all internal mapping expressions will be lost)