表达式树对象转换器

定义两个对象

public class Person
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
}
public class NewPerson
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
}

创建表达式树转换器

public class ExpressionMapper<TIn, TOut>
    {
        private static Func<TIn, TOut> _mapper = null;
        static ExpressionMapper()
        {
            ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "x");
            List<MemberBinding> bindings = new List<MemberBinding>();

            foreach (var property in typeof(TOut).GetProperties())
            {
                MemberExpression member = Expression.Property(parameterExpression, typeof(TIn).GetProperty(property.Name));
                MemberBinding binding = Expression.Bind(property, member);   // x=>x.Id
                bindings.Add(binding);
            }

            MemberInitExpression memberInitExpression = Expression.MemberInit(Expression.New(typeof(TOut)), bindings.ToArray());  //new newPersion(){Id=x.Id,Name=x.Name,Age=x.Aget}

            var funcExp = Expression.Lambda<Func<TIn, TOut>>(memberInitExpression, parameterExpression);  //  x=> new newPersion(){Id=x.Id,Name=x.Name,Age=x.Aget}
            _mapper = funcExp.Compile();
        }

        public static TOut Mapper(TIn sour)
        {
            return _mapper(sour);
        }
    }

源对象转换为目标对象

var person = new Person()
{
    Id = 1,
    Name = "张三",
    Age = 2
};

var newPersion = ExpressionMapper<Person, NewPerson>.Mapper(person);