需要加快automapper ......它需要32秒做113对象 [英] Need to speed up automapper...It takes 32 seconds to do 113 objects

问题描述

您好我有自动映射的一些重大问题，并很慢。我不知道如何加快速度。

Hi I have some major problems with auto mapper and it being slow. I am not sure how to speed it up.

我使用NHibernate，流利NHibernate和asp.net MVC 3.0

I am using nhibernate,fluent nhibernate and asp.net mvc 3.0

[Serializable()]
    public class Test
    {
        public virtual int Id { get; private set; }
        public virtual string Name { get;  set; }
        public virtual string Description { get; set; }
        public virtual DateTimeDate { get; set; }
        public virtual IList<Reminder> Reminders { get; set; }
        public virtual IList<Reminder2> Reminders2 { get; set; }
        public virtual Test2 Test2 { get; set; }

        public Test()
        {
            Reminders = new List<Reminders>();
            Reminders2 = new List<Reminders2>();
        }

    }

因此​​，大家可以看到我得到了一些特性，其他一些类作为我的数据库我有他们之间的引用。

So as you can see I got some properties, Some other classes as in my database I have references between them.

然后我做到这一点。

var a = // get all items (returns a collection of Test2)
var List<MyViewModel> collection = new List<MyViewModel>();
     foreach (Test2 t in a)
            {
                MyViewModel vm = Mapper.Map<Test2, MyViewModel>(t);
                vm.SetDateFormat(t.DateTimeDate, DateFilters.All.ToString());

                collection.Add(vm);
            }

//浏览模式

    public class MyViewModel
        {
            public int Id  { get; private set; }
            public string Name { get; set; }
            public string Description { get; set; }
            public DateTime DateTimeDate { get; set; }
            public string FormatedDueDate { get; set; }
            public string Test2Prefix { get; set; }
            public string Test2BackgroundColor { get; set; }
            public string SelectedDateFilter { get; set; }
            public bool DescState { get; set; }
            public bool AlertState { get; set; }


            /// <summary>
            /// Constructor
            /// </summary>
            public MyViewModel()
            {
                // Default values
                SelectedDateFilter = "All";
                DescState = false;
                AlertState = false;
            }

            /// <summary>
            /// Sets the date formatter string used
            /// </summary>
            /// <param name="dateFormat"></param>
            public void SetDateFormat(DateTime dueDate, string dateFilter)
            {
                // simple if statement to format date.
            }
        }

//映射

  Mapper.CreateMap<Test2,MyViewModel>().ForMember(dest => dest.DescState, opt =>
 opt.ResolveUsing<DescStateResolver>())
                 .ForMember(dest => dest.AlertState, opt =>
 opt.ResolveUsing<AlertStateResolver>());

//解析器

public class AlertStateResolver : ValueResolver<Task, bool>
    {
        protected override bool ResolveCore(Task source)
        {
            if (source.Reminders.Count > 0 || source.Reminders2.Count > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }   

  public class DescStateResolver : ValueResolver<Task,bool>
    {
        protected override bool ResolveCore(Task source)
        {
            if (String.IsNullOrEmpty(source.Description))
            {
                return false;
            }
            else
            {
                return true;
            }
        }
    }

忽略怪异的名字和任何错别字我真正的目标工作得很好，很有意义。

Ignore the weird names and any typos my real object works just fine and makes sense.

所以我用秒表，这样做

Stopwatch a = new Stopwatch()
    foreach (Test2 t in a)
                {
                    a.Start()                     
                    MyViewModel vm = Mapper.Map<Test2, MyViewModel>(t);
                    a.Stop()
                    vm.SetDateFormat(t.DateTimeDate, DateFilters.All.ToString());

                    collection.Add(vm);
                }

var b = a.Elapsed; // comes back with 32 seconds.

我需要非常糟糕的优化这一点。

I need to optimized this very badly.

推荐答案

而不是：

var a = // get all items (returns a collection of Test2)
List<MyViewModel> collection = new List<MyViewModel>();
foreach (Test2 t in a)
{
    MyViewModel vm = Mapper.Map<Test2, MyViewModel>(t);
    vm.SetDateFormat(t.DateTimeDate, DateFilters.All.ToString());
    collection.Add(vm);
}

尝试：

var a = // get all items (returns a collection of Test2)
List<MyViewModel> collection = Mapper.Map<IEnumerable<Test2>, IEnumerable<MyViewModel>>(a);

这是等同于第一除 SetDateFormat 通话，你可以在你的映射定义做。这也可能会更快。

which is equivalent to the first except the SetDateFormat call which you could do at your mapping definition. It might also be faster.

如果您有的Test2 =＆GT之间定义的映射; MyViewModel AutoMapper自动提供一个用于的IEnumerable＆LT;＆的Test2 GT; = GT; IEnumerable的＆LT; MyViewModel方式＆gt; ，这样你就不需要循环

If you have a mapping defined between Test2 => MyViewModel AutoMapper automatically provides one for IEnumerable<Test2> => IEnumerable<MyViewModel> so that you don't need to loop.

您已经在你的问题中提到的NHibernate也。确保其藏品沿着你的源对象急切地从数据库中加载的之前将它传递给映射层或者你不能责怪AutoMapper为是缓慢的，因为当它试图绘制的收藏品之一的源对象是访问数据库，因为NHibernate的不取此集合。

Also you have mentioned NHibernate in your question. Make sure that your source object along with its collections is eagerly loaded from the database before passing it to the mapping layer or you cannot blame AutoMapper for being slow because when it tries to map one of the collections of your source object it hits the database because NHibernate didn't fetch this collection.

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