程式隨筆
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AutoMapper運用

Posted on Edited on Disqus:

寫網站常常會遇到從ViewModel對應到應用程式的DTO，或是DB的物件問題，以前自己的做法都是

```csharp public bool Login(LoginViewModel model) { Account account = new Account() { Account = model.Account, Password = model.Password } var Result = _AccountService.Loign(account ); return Result; }

public class LoginViewModel
{
public string Account{get;set;}
public string Password{get;set;}
}

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等到內部運作完畢的時候可能又要把對應的DTO處理成ViewModel在拋回頁面，這種反覆一直寫的動作其實真的很煩人，直到最近同事介紹了[AutoMapper](https://www.nuget.org/packages/AutoMapper/)給我們之後，整個流程得到了大幅度的改善。

*   AutoMapper的基本運用

    當兩個物件的屬性都一樣時，AutoMapper會自動去對應並且轉出
[![](http://4.bp.blogspot.com/-j6G1kaI6BXw/VimtMro_B9I/AAAAAAAAHgY/qZYVfNriOm0/s1600/1.png)](http://4.bp.blogspot.com/-j6G1kaI6BXw/VimtMro_B9I/AAAAAAAAHgY/qZYVfNriOm0/s1600/1.png)

    如果兩個物件的屬性對應略有不同，也可以加上規則

    [![](http://1.bp.blogspot.com/-n04XweFHx5w/VimuRLyJtGI/AAAAAAAAHgg/H0pNXYnW11w/s1600/1.png)](http://1.bp.blogspot.com/-n04XweFHx5w/VimuRLyJtGI/AAAAAAAAHgg/H0pNXYnW11w/s1600/1.png)
*   如果兩的類別對應到同一個物件的情況
    ```csharp
void Main()
{
 AccountViewModel model = new AccountViewModel() {
  Account = "toyo",
  Password = "pwd",
  City = "Taipei",
  District = "大安"
 };
 var Group = new Group() {
  ID = 1,
  Name = "客戶群組"
 };
 Mapper.CreateMap<AccountViewModel,AccountDTO>()
  .ForMember(d=> d.Address , o=>o.MapFrom(s=>string.Concat(s.City,s.District))); var account = Mapper.Map<AccountDTO>(model);

        //這邊用上面已經轉好的account,來接續Mapper
 Mapper.CreateMap<Group, AccountDTO>()
  .ForMember(d => d.Account, o => o.Ignore())
  .ForMember(d => d.Password, o => o.Ignore())
  .ForMember(d => d.Address, o => o.Ignore())
  .ForMember(d => d.GroupName, o => o.MapFrom(s=>s.Name));
    //注意
 account = Mapper.Map<Group,AccountDTO>(Group,account);

     account.Dump();
}

    public class AccountViewModel
{
 public string Account { get; set; }
 public string Password { get; set; }
 public string City { get; set; }
 public string District {get;set;}
}

    public class AccountDTO
{
 public string Account { get; set; }
 public string Password { get; set; }
 public string Address { get; set; }
 public string GroupName {get;set;}
}

    public class Group{
 public int ID { get; set; }
 public string Name {get;set;}
}

結果

最後,在MVC的網站裡面使用AutoMapper可以在把所有規則都先寫在ProFile裡面，然後在Global一次註冊，之後在程式裡面用到就不用每次再寫CreateMap的部分
**Profile : ** 
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public class ControllerMappingProfile : Profile
{
 public override string ProfileName
 {
  get
  {
   return "ControllerMappingProfile";
  }
 }

 protected override void Configure()
 {
  Mapper.CreateMap<AccountViewModel, AccountDTO>()
   .ForMember(d => d.Address, o => o.MapFrom(s => string.Concat(s.City, s.District)));

  Mapper.CreateMap<Group, AccountDTO>()
      .ForMember(d => d.Account, o => o.Ignore())
      .ForMember(d => d.Password, o => o.Ignore())
      .ForMember(d => d.Address, o => o.Ignore())
      .ForMember(d => d.GroupName, o => o.MapFrom(s => s.Name));
 }
}

**AutoMapperConfig : **

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public class AutoMapperConfig
    {
        public static void Configure()
        {
            Mapper.Initialize(x =>
            {
                x.AddProfile<ControllerMappingProfile>();
            });
        }
    }

最後在Global Application_Start註冊即可 ```csharp
protected void Application_Start()
{
AutoMapperConfig.Configure();
}