ExpressionTreeHelper 表达式树泛型委托拷贝方法

var people = new People()
{
    Id = 11,
    Name = "Richard",
    Age = 31
};
int count = 1_000_000;
var common = HiPerfTimer.Execute(() =>
{
    for (int i = 0; i < count; i++)
    {
        var item = new PeopleCopy()
        {
            Id = people.Id,
            Name = people.Name,
            Age = people.Age,
        };
    }
});
Console.WriteLine(string.Format("common={0} ms", common));

var serialize = HiPerfTimer.Execute(() =>
{
    PeopleCopy item = new PeopleCopy();
    for (int i = 0; i < count; i++)
    {
        var rslt = JsonConvert.SerializeObject(people);
        item = JsonConvert.DeserializeObject<PeopleCopy>(rslt);
    }
});
Console.WriteLine(string.Format("serialize={0} ms", serialize));

var generic = HiPerfTimer.Execute(() =>
{
    PeopleCopy item = new PeopleCopy();
    for (int i = 0; i < count; i++)
    {
        item = ExpressionTreeHelper<PeopleCopy>.EntityMap(people);
    }
});
Console.WriteLine(string.Format("generic={0} ms", generic));

var copy = HiPerfTimer.Execute(() =>
{
    PeopleCopy item = new PeopleCopy();
    for (int i = 0; i < count; i++)
    {
        var aa = people.DeepCopy();
    }
});
Console.WriteLine(string.Format("DeepCopy={0} ms", copy));

 public class ExpressionTreeHelper<T>
 {
     public static T EntityMap<TSrc>(TSrc src)
     {
         return ExpressionGenericMapper<TSrc, T>.EntityMap(src);
     }
 }

 internal class ExpressionGenericMapper<TSrc, TDst>
 {
     private static readonly Func<TSrc, TDst> _func = null;

     static ExpressionGenericMapper()
     {
         var parameterExpression = Expression.Parameter(typeof(TSrc), "e");
         var list = new List<MemberBinding>();
         foreach (var item in typeof(TDst).GetProperties())
         {
             var property = Expression.Property(parameterExpression, typeof(TSrc).GetProperty(item.Name));
             var binding = Expression.Bind(item, property);
             list.Add(binding);
         }
         foreach (var item in typeof(TDst).GetFields())
         {
             var property = Expression.Field(parameterExpression, typeof(TSrc).GetField(item.Name));
             var binding = Expression.Bind(item, property);
             list.Add(binding);
         }

         var miExpression = Expression.MemberInit(Expression.New(typeof(TDst)), list.ToArray());
         var lambda = Expression.Lambda<Func<TSrc, TDst>>(miExpression, new[]
         {
             parameterExpression
         });
         _func = lambda.Compile();
     }

     public static TDst EntityMap(TSrc obj)
     {
         return _func(obj);
     }
 }