AutoMapper的配置方法

AutoMapper與ASP.NET MVC結合，一般會在Controller的Action中使用AutoMapper把前台傳遞過來的Presentation Model轉換成相應的業務邏輯上的Entity Model.如果在Action中寫AutoMapper.CreateMap<T1,T2>,這些代碼未免與業務邏輯無多大關系，所以不應該寫在Action中。我們可以利用ASP.NET MVC中的Filter這個特點，以過濾器的方式在執行Action中AutoMapper的轉換前就完成配置。

首先，要定義一個MyProfile, 繼承自AutoMapper的Profile類，並且重寫Configure()方法，在這個方法中進行配置。
[csharp]
public class OrderDomainMvcProfile : Profile 
    { 
        public override string ProfileName 
        { 
            get { return "OrderDomainMvcProfile"; } 
        } 
 
        protected override void Configure() 
        { 
            // Map……  
        Mapper.CreateMap<T1, T2>().ForMember(……)； 
    } 
} 

public class OrderDomainMvcProfile : Profile
    {
        public override string ProfileName
        {
            get { return "OrderDomainMvcProfile"; }
        }

        protected override void Configure()
        {
            // Map……
     Mapper.CreateMap<T1, T2>().ForMember(……)；
 }
}然後再Filter中進行加載

[csharp]
[AttributeUsageAttribute(AttributeTargets.Class |AttributeTargets.Method, Inherited = false, AllowMultiple = false)] 
public class AutoMapperConfigurationActionFilterAttribute : FilterAttribute 
{ 
    public AutoMapperConfigurationActionFilterAttribute(Type profileType) 
    { 
       Mapper.Configuration.AddProfileThreadSafe(Activator.CreateInstance(profileType) as Profile); 
    } 
} 

[AttributeUsageAttribute(AttributeTargets.Class |AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
public class AutoMapperConfigurationActionFilterAttribute : FilterAttribute
{
    public AutoMapperConfigurationActionFilterAttribute(Type profileType)
    {
       Mapper.Configuration.AddProfileThreadSafe(Activator.CreateInstance(profileType) as Profile);
    }
}最後把Filter應用到Controller的Action
[csharp]
[AutoMapperConfigurationActionFilter(typeof(OrderDomainMvcProfile))] 
public virtual ActionResult OrderGrid_Select(GridCommand command) 
{ ……         
} 

[AutoMapperConfigurationActionFilter(typeof(OrderDomainMvcProfile))]
public virtual ActionResult OrderGrid_Select(GridCommand command)
{ ……       
}

這裡介紹另外一種比較特別的方法。我希望在程序剛剛開始啟動，即Application_Start的時候，就完成所有的配置，一勞永逸。如果ASP.NET MVC有多個Domain對應多個Area,那麼在global.asax.cs中Application_Start中就要寫很多配置AutoMapper的代碼。這裡我們使用反射，去尋找DLL中實現了IStartupTask的接口的方法，然後運行Excecute方法即可。

創建一個IStartupTask接口

[csharp]
public interface IStartupTask 
{ 
    void Execute(); 
} 

public interface IStartupTask
{
    void Execute();
}實現這個接口
[csharp]
public class AutoMapperStartupTask : IStartupTask 
 { 
        public void Execute() 
        { 
            
            Create<User, UserModel>(); 
            Create<Widget, WidgetModel>(); 
            Create<WidgetDefinition, WidgetDefinitionModel>(); 
 
            //Mapper.CreateMap<ModuleDefinition, ModuleDefinitionModel>()  
            //  .ForMember(m => m.AppId, o => o.MapFrom(e => e.App == null ? (int?)null : e.App.Id))  
            //  .ForMember(m => m.AppTitle, o => o.MapFrom(e => e.App == null ? null : e.App.Title));  
            //Mapper.CreateMap<ModuleDefinitionModel, ModuleDefinition>();  
 
        } 
 
        protected virtual void Create<T1, T2>() 
        { 
            Mapper.CreateMap<T1, T2>(); 
            Mapper.CreateMap<T2, T1>(); 
        } 
 } 

public class AutoMapperStartupTask : IStartupTask
 {
        public void Execute()
        {
          
            Create<User, UserModel>();
            Create<Widget, WidgetModel>();
            Create<WidgetDefinition, WidgetDefinitionModel>();

            //Mapper.CreateMap<ModuleDefinition, ModuleDefinitionModel>()
            //  .ForMember(m => m.AppId, o => o.MapFrom(e => e.App == null ? (int?)null : e.App.Id))
            //  .ForMember(m => m.AppTitle, o => o.MapFrom(e => e.App == null ? null : e.App.Title));
            //Mapper.CreateMap<ModuleDefinitionModel, ModuleDefinition>();

        }

        protected virtual void Create<T1, T2>()
        {
            Mapper.CreateMap<T1, T2>();
            Mapper.CreateMap<T2, T1>();
        }
 }
在Global.ascx中一次性引入所有的AutoMapper配置
[csharp]
protected void Application_Start() 
{ 
     …… 
     ExecuteStartupTasks(); 
} 
 
 
private void ExecuteStartupTasks() 
{ 
            List<IStartupTask> startupTasks = new List<IStartupTask>(); 
            Assembly asm = this.ExecutingAssembly; 
 
            // get path of executing (bin) folder from the current executing assembly  
            string codeBase = this.ExecutingAssembly.CodeBase; 
            UriBuilder uri = new UriBuilder(codeBase); 
            string path = Uri.UnescapeDataString(uri.Path); 
            string bin = Path.GetDirectoryName(path); 
            string[] assemblies = Directory.GetFiles(bin, "*.dll"); 
 
            foreach (String file in assemblies) 
            { 
                try 
                { 
                    if (File.Exists(file)) 
                    { 
                        // load the assembly  
                        asm = Assembly.LoadFrom(file); 
 
                        // get all types from the assembly that inherit IStartupTask  
                        var query = from t in asm.GetTypes() 
                                    where t.IsClass && t.GetInterface(typeof(IStartupTask).FullName) != null 
                                    select t; 
 
                        // add types to list of startup tasks  
                        foreach (Type type in query) 
                        { 
                            startupTasks.Add((IStartupTask)Activator.CreateInstance(type)); 
                        } 
                    } 
                } 
                catch (Exception ex) 
                { 
                    Exceptions.LogException(ex); 
                } 
            } 
 
            // execute each startup task  
            foreach (IStartupTask task in startupTasks) 
            { 
                task.Execute(); 
            } 
}