[英]Mapping DTO to Entity while TrackingChanges with AutoMapper and EFCore
對AutoMapper和EFCore來說是非常新的東西,所以也許比我在這里所能做的要多得多,但我想我可以嘗試一下,但是失敗了,也許沒有可能,但是如果有人可以指出我正確的方向。
我正在使用AutoMapper將我的實體轉換為DTO,這很好。
現在我想將我的DTO轉換為一個實體,並讓EntityFramework跟蹤所有更改(屬性更新,從列表中刪除子對象等),但是這可能嗎?
因此,如果我有一個簡單的PUT方法,我想做這樣的事情,然后讓automapper整理其余的內容
public async Task<IActionResult> PutAsync([FromBody] MyDTO model)
{
// GET OBJECT FROM DATABASE HERE
var dbValue = _repos.GetMyObjectUsingId(999);
// apply updates
_mapper.Map<MyDTO, MyObject>(dbValue, model);
}
您可以創建一個適配器類,以便您的更改集保持不變:您是否從接口繼承了DTO?
假設您有一個DTO:
public interface IFooDTO
{
int Id { get; set;}
string Name { get; set;}
}
public class FooDTO : IFooDTO
{
public int Id { get; set;}
public string Name { get; set; }
}
然后你有你的實體
public class FooEntity
{
public int Id;
public string name;
}
然后像這樣創建您的適配器,該適配器繼承自foo接口:
public class FooAdapter : IFooDTO
{
FooEntity entity;
FooAdapter(FooEntity entity)
{
this.entity = entity;
}
public int Id
{
get {return this.entity.Id;}
set {/*Do nothing set by EF*/}
}
public string Name
{
get {return this.entity.Name;}
set {this.entity.Name = value; }
}
public void Apply(FooDTO foo)
{
//I don't remember if this is the correct order but you get the gyst
this._mapper.Map<IFooDTO, IFooDTO>(this, foo);
}
}
然后,您只需要在映射器中將您的Idto映射到您的dto。
用法:
public ActionResult PutFoo(int id, FooDTO foo)
{
var entity = context.Foos.FirstOrDefault(x => x.Id == id);
var adapter = new FooAdapter(entity);
adapter.Apply(foo);
//Entity has been updated and has original changes
}
編輯
兒童工作正常,只是使用相同的適配器模式,因此設置程序的設置很多,但是
public BarDTO childBar
{
get { return new BarAdapter(this.entity.Bar).ToDTO(); }
set { new BarAdapter(this.entity.Bar).Apply(value) }
}
同步實體:
public static void Sync<TEntity, TEntityKey, TDTO>(this ICollection<TEntity> entityCollection, ICollection<TDTO> dtoCollection,
Func<TEntity> entityConstructor, Action<TDTO, TEntity> copyAction,
Action<TEntity> onDeleteAction,
Func<TEntity, TEntityKey> entityKeySelector,
Func<TDTO, TEntityKey> dtoKeySelector)
where TEntity : class
where TEntityKey : struct
{
dtoCollection = dtoCollection ?? new TDTO[] { };
except = except ?? new TEntityKey[] { };
var dtoIds = dtoCollection.Select(dto => dtoKeySelector(dto)).ToHashSet();
foreach (var entity in entityCollection.Where(x => false == dtoIds.Contains(entityKeySelector(x))).ToArray())
{
onDeleteAction(entity);
entityCollection.Remove(entity);
}
var entityCollectionMap = entityCollection.ToDictionary(x => entityKeySelector(x));
foreach (var dtoItem in dtoCollection)
{
TEntity entity = null;
if (dtoKeySelector(dtoItem).HasValue)
{
entity = entityCollectionMap.ContainsKey(dtoKeySelector(dtoItem)) ? entityCollectionMap[dtoKeySelector(dtoItem)] : default(TEntity);
}
if (null == entity)
{
entity = entityConstructor();
entityCollection.Add(entity);
}
copyAction(dtoItem, entity);
}
}
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