[英]Mapping DTO back to model with AutoMapper
我有一個Fixture模型:
public partial class Fixture
{
public int FixtureId { get; set; }
public string Season { get; set; }
public byte Week { get; set; }
//foreign key
public int AwayTeamId { get; set; }
//navigation properties
public virtual Team AwayTeam { get; set; }
//foreign key
public int HomeTeamId { get; set; }
//navigation properties
public virtual Team HomeTeam { get; set; }
public byte? AwayTeamScore { get; set; }
public byte? HomeTeamScore { get; set; }
}
還有一個夾具DTO:
public class FixtureDTO
{
public int Id { get; set; }
public string Season { get; set; }
public byte Week { get; set; }
public string AwayTeamName { get; set; }
public string HomeTeamName { get; set; }
public byte? AwayTeamScore { get; set; }
public byte? HomeTeamScore { get; set; }
}
我正在使用AutoMapper進行映射,這是我第一次嘗試使用它。 這是我的映射:
CreateMap<Fixture, FixtureDTO>()
.ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.FixtureId))
.ForMember(dest => dest.AwayTeamName, opt => opt.MapFrom(src => src.AwayTeam.TeamName))
.ForMember(dest => dest.HomeTeamName, opt => opt.MapFrom(src => src.HomeTeam.TeamName));
CreateMap<FixtureDTO, Fixture>();
在使用Fixture並將其映射到我用來顯示數據的FixtureDTO時,它可以很好地工作。 但是,當我想更新數據並將FixtureDTO傳遞回以將其映射回Fixture時,出現錯誤。
public HttpResponseMessage PutFixture(int id, FixtureDTO fixture)
{
if (ModelState.IsValid && id == fixture.Id)
{
//do mapping manually here?
var updated = _repository.UpdateFixture(Mapper.Map<Fixture>(fixture));
return Request.CreateResponse(updated ? HttpStatusCode.OK : HttpStatusCode.NotFound);
}
return Request.CreateResponse(HttpStatusCode.BadRequest);
}
這是我得到的錯誤:
Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.
有人可以幫忙嗎?
編輯:反向映射:
CreateMap<Fixture, FixtureDTO>()
.ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.FixtureId))
.ForMember(dest => dest.AwayTeamName, opt => opt.MapFrom(src => src.AwayTeam.TeamName))
.ForMember(dest => dest.HomeTeamName, opt => opt.MapFrom(src => src.HomeTeam.TeamName));
CreateMap<FixtureDTO, Fixture>()
.ForMember(dest => dest.FixtureId, opt => opt.MapFrom(src => src.Id))
.ForMember(dest => dest.AwayTeam.TeamName, opt => opt.MapFrom(src => src.AwayTeamName))
.ForMember(dest => dest.HomeTeam.TeamName, opt => opt.MapFrom(src => src.HomeTeamName));
通常,當EF檢測到以下情況之一時,就會引發該異常:
樂觀並發沖突 :通常在修改您要編輯的實體時發生,否則會在您加載,編輯和保存該實體的時間進行修改。 (請參閱: 實體框架:“存儲更新,插入或刪除語句影響了意外的行數(0)。” )
ID設置不正確 :未為Pks或FK 設置ID 。 當我錯誤地將Entity的FK設置為值並將關聯的對象設置為具有不同ID的對象時,我也看到了這樣的異常。
由於存儲庫中的某些代碼,很可能引發此異常。 如果將代碼發布到存儲庫中,我們可能會更好地了解導致異常的原因。
首先,您需要創建從DTO到實體的反向映射(如果需要,提供自定義成員映射):
Mapper.CreateMap<FixtureDTO, Fixture>();
其次-檢索,映射和更新現有實體
if (ModelState.IsValid && id == fixture.Id)
{
Fixture entity = _repository.FindById(fixture.Id);
Mapper.Map(fixture, entity); // Use this mapping method!
var updated = _repository.UpdateFixture(entity);
// etc
}
@lazyberezovsky答案的擴展:
這是您可能需要的反向映射的一個(未經測試的)示例:
CreateMap<FixtureDTO, Fixture>()
.ForMember(dest => dest.FixtureId,
opt => opt.MapFrom(src => src.Id))
.ForMember(dest => dest.AwayTeam,
opt => opt.MapFrom(src => new Team
{
TeamName = src.AwayTeamName
}))
.ForMember(dest => dest.HomeTeam,
opt => opt.MapFrom(src => new Team
{
TeamName = src.HomeTeamName
}));
我過去曾經使用過這種格式,並且效果很好,但也可以為團隊創建特定的映射。 例如:
CreateMap<string, Team>()....
另外,我假設您正在執行此操作,但是斷言您的配置有效。 例如:
[Test]
public void AutoMapper_Configuration_IsValid()
{
Mapper.Initialize(m => m.AddProfile<MyProfile>());
Mapper.AssertConfigurationIsValid();
}
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