public class TestA
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public TestC TestClass { get; set; }

        public IEnumerable<TestC> TestLists { get; set; }
    }

    public class TestB
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public TestD TestClass { get; set; }

        public TestD[] TestLists { get; set; }
    }

    public class TestC
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public TestC SelfClass { get; set; }
    }

    public class TestD
    {
        public int Id { get; set; }
        public string Name { get; set; }

        public TestD SelfClass { get; set; }
    }

var mode=new TestA();
TestB b = Mapper<TestA, TestB>.Map(model);

var a = new TestA();
a.ID = 1;
var b = new TestB();
Mapper<TestA, TestB>.Map(a ,b);