1

我有一个夹具模型：

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; }
}

和夹具 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 进行映射，这是我第一次尝试使用它。这是我的映射：

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>();

它可以很好地获取 Fixture 并将其映射到我用来显示数据的 FixtureDTO。但是，当我想更新数据并将 FixtureDTO 传回以将其映射回 Fixture 时，我得到了一个错误。

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);
    }

这是我得到的错误：

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.

有人可以帮忙吗？

编辑：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));
4

3 回答 3

0

通常，当 EF 检测到以下情况之一时，会引发该异常：

乐观并发违规：这通常发生在您尝试编辑的实体在您加载、编辑和保存期间的其他地方被修改时。（请参阅：实体框架：“存储更新、插入或删除语句影响了意外数量的行 (0)。”）

错误设置的 ID：没有为 Pks 或 FK 设置 ID。当我错误地将实体的 FK 设置为一个值并将关联的对象设置为具有不同 ID 的对象时，我也看到过这样的异常。

由于存储库中的某些代码，很可能会引发此异常。如果您将代码发布到您的存储库中，我们可能会更好地了解导致异常的原因。

于 2012-11-29T19:45:50.587 回答
0

首先，您需要创建从 DTO 到实体的反向映射（如果需要，提供自定义成员映射）：

Mapper.CreateMap<FixtureDTO, Fixture>();

第二 - 检索、映射和更新现有实体

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
}
于 2012-11-29T19:47:02.927 回答
0

@lazyberezovsky 答案的扩展：

这是您可能需要的反向映射的（未经测试的）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
                                                 }));

我过去使用过这种格式并且效果很好，但是您也可以为团队创建特定的映射。例如：

CreateMap<string, Team>()....

另外，我假设您正在这样做，但断言您的配置是有效的。例如：

[Test]
public void AutoMapper_Configuration_IsValid()
{
    Mapper.Initialize(m => m.AddProfile<MyProfile>());
    Mapper.AssertConfigurationIsValid();
}
于 2012-11-30T00:48:58.610 回答