对象拷贝

转载于：https://www.cnblogs.com/lsgsanxiao/p/8205096.html（强力推荐）

我只是代码的搬运工

/// <summary>
    /// 
    /// </summary>
    /// <typeparam name="TIn"></typeparam>
    /// <typeparam name="TOut"></typeparam>
    public static class TransExpV2<TIn, TOut>
    {
        /// <summary>
        /// 通过表达式树复制对象
        /// </summary>
        private static readonly Func<TIn, TOut> cache = GetFunc();
        private static Func<TIn, TOut> GetFunc()
        {
            ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "p");
            List<MemberBinding> memberBindingList = new List<MemberBinding>();

            foreach (var item in typeof(TOut).GetProperties())
            {
                if (!item.CanWrite)
                    continue;

                MemberExpression property = Expression.Property(parameterExpression, typeof(TIn).GetProperty(item.Name));
                MemberBinding memberBinding = Expression.Bind(item, property);
                memberBindingList.Add(memberBinding);
            }

            MemberInitExpression memberInitExpression = Expression.MemberInit(Expression.New(typeof(TOut)), memberBindingList.ToArray());
            Expression<Func<TIn, TOut>> lambda = Expression.Lambda<Func<TIn, TOut>>(memberInitExpression, new ParameterExpression[] { parameterExpression });

            return lambda.Compile();
        }

        /// <summary>
        /// 入口
        /// </summary>
        /// <param name="tIn"></param>
        /// <returns></returns>
        public static TOut Trans(TIn tIn)
        {
            return cache(tIn);
        }