自动映射器:手动映射属性

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我刚刚开始使用automapper映射DTO 实体，它似乎工作得很好.

I just started to use automapper to map DTOs<->Entities and it seems to be working great.

在某些特殊情况下，我只想映射某些属性并执行其他检查.没有自动映射器，代码如下所示(使用fasterflect的PropertyExtensions):

In some special cases I want to map only some properties and perform additional checks. Without automapper the code looks like this (using fasterflect's PropertyExtensions):

object target; object source; string[] changedPropertyNames = { }; foreach (var changedPropertyName in changedPropertyNames) { var newValue = source.GetPropertyValue(changedPropertyName); target.SetPropertyValue(changedPropertyName, newValue); }

当然，如果需要类型转换，则此代码将不起作用. Automapper使用内置的TypeConverters，我还创建了一些特定的TypeConverter实现.

Of course this code won't work if type conversions are required. Automapper uses built-in TypeConverters and I also created some specific TypeConverter implementations.

现在，我想知道是否可以映射单个属性并使用automapper的类型转换实现

Now I wonder whether it is possible to map individual properties and use automapper's type conversion implementation, something like this

Mapper.Map(source, target, changedPropertyName);

更新

我认为需要更多信息:

Update

I think more information is necessary:

我已经创建了一些地图，例如

I already created some maps, e.g.

Mapper.CreateMap<CalendarEvent, CalendarEventForm>()

并且我还为CalendarEvent中的可为null的dateTime属性创建了一个带有自定义类型转换器的地图，例如

and I also created a map with a custom typeconverter for the nullable dateTime property in CalendarEvent, e.g.

Mapper.CreateMap<DateTimeOffset?, DateTime?>().ConvertUsing<NullableDateTimeOffsetConverter>();

我在Web API OData Controller中使用这些映射.发布新的EntityDTO时，我使用

I use these maps in a web api OData Controller. When posting new EntityDTOs, I use

Mapper.Map(entityDto, entity);

，然后将实体保存到数据存储中.

and save the entity to a datastore.

但是如果使用PATCH，则会将Delta<TDto> entityDto传递给我的控制器方法.因此，我需要调用entityDto.GetChangedPropertyNames()并使用更改后的值更新我现有的持久性实体.

But if using PATCH, a Delta<TDto> entityDto is passed to my controller methods. Therefore I need to call entityDto.GetChangedPropertyNames() and update my existing persistent entity with the changed values.

基本上，这可以与我的简单解决方案一起使用，但是如果更改的属性之一是DateTimeOffset?我想使用我的NullableDateTimeOffsetConverter.

Basically this is working with my simple solution, but if one of the changed properties is e.g. a DateTimeOffset? I would like to use my NullableDateTimeOffsetConverter.

推荐答案

如果您只想映射某些select属性，而不必执行以下操作

If you just want to map only some select property than you have to do as below

// Create a map var map = CreateMap<Source,Target>(); // ingnore all existing binding of property map.ForAllMembers(opt => opt.Ignore()); // than map property as following map.ForMember(dest => dest.prop1, opt => opt.MapFrom( src => src.prop1)); map.ForMember(dest => dest.prop2, opt => opt.MapFrom( src => src.prop2));