AutoMapper Model To ViewModel Vice Versa 更新记录

Question

我有一个单元测试，我使用映射器从 Model 到 ViewModel，然后 ViewModel 返回到 Model 更新记录 - 但实际上我没有更改任何内容，只是测试更新是否有效。

        [TestMethod]
    public void UpdateEntry()
    {
        //Map Model to ViewModel
        Mapper.CreateMap<GlobalExport, GlobalExportViewModel>();
        Mapper.CreateMap<FileNameSetup, FileNameSetupViewModel>();
        Mapper.CreateMap<FileNameVariable, FileNameVariableViewModel>();
        Mapper.CreateMap<EmailSetup, EmailSetupViewModel>();
        Mapper.CreateMap<SelectedSection, SelectedSectionViewModel>();
        Mapper.CreateMap<AvailableSection, AvailableSectionViewModel>();
        Mapper.CreateMap<AvailableColumn, AvailableColumnViewModel>();
        Mapper.CreateMap<Policy, PolicyViewModel>();
        Mapper.CreateMap<SelectedColumn, SelectedColumnViewModel>();
        Mapper.CreateMap<SelectedEmployeeSeaServiceType, SelectedEmployeeSeaServiceTypeViewModel>();
        Mapper.CreateMap<SelectedEmployeeStatus, SelectedEmployeeStatusViewModel>();
        Mapper.CreateMap<EmployeeStatus, EmployeeStatusViewModel>();
        Mapper.CreateMap<EmployeeSubStatus, EmployeeSubStatusViewModel>();
        Mapper.CreateMap<SelectedEmployeeSubStatus, SelectedEmployeeSubStatusViewModel>();
        Mapper.CreateMap<SelectedSeaServiceType, SelectedSeaServiceTypeViewModel>();


        GlobalExport globalExport = _service.GetGlobalExportById(1);
        GlobalExportViewModel globalExportViewModel = Mapper.Map<GlobalExport, GlobalExportViewModel>(globalExport);

        //Map ViewModel to Model
        Mapper.CreateMap<GlobalExportViewModel, GlobalExport>();
        Mapper.CreateMap<FileNameSetupViewModel, FileNameSetup>();
        Mapper.CreateMap<FileNameVariableViewModel, FileNameVariable>();
        Mapper.CreateMap<EmailSetupViewModel, EmailSetup>();
        Mapper.CreateMap<SelectedSectionViewModel, SelectedSection>();
        Mapper.CreateMap<AvailableSectionViewModel, AvailableSection>();
        Mapper.CreateMap<AvailableColumnViewModel, AvailableColumn>();
        Mapper.CreateMap<PolicyViewModel, Policy>();
        Mapper.CreateMap<SelectedColumnViewModel, SelectedColumn>();
        Mapper.CreateMap<SelectedEmployeeSeaServiceTypeViewModel, SelectedEmployeeSeaServiceType>();
        Mapper.CreateMap<SelectedEmployeeStatusViewModel, SelectedEmployeeStatus>();
        Mapper.CreateMap<EmployeeStatusViewModel, EmployeeStatus>();
        Mapper.CreateMap<EmployeeSubStatusViewModel, EmployeeSubStatus>();
        Mapper.CreateMap<SelectedEmployeeSubStatusViewModel, SelectedEmployeeSubStatus>();
        Mapper.CreateMap<SelectedSeaServiceTypeViewModel, SelectedSeaServiceType>();

        GlobalExport newGlobalExport = Mapper.Map<GlobalExportViewModel, GlobalExport>(globalExportViewModel);
        _service.UpdateGlobalExport(newGlobalExport);

    }

我收到此错误：

有人可以给出一些意见或更好的解决方案吗：P 非常感谢！

Answer 1

这里的问题是GlobalExportRepository.UpdateGlobalExport 方法试图将GlobalExport 对象附加到检索它的同一DbContext 实例。

尝试修改GlobalExportRepository.UpdateGlobalExport 方法以将实体显式标记为已修改，然后只需调用DbContext.SaveChanges 方法即可。

这是一个例子：

public void UpdateGlobalExport(GlobalExport instance)
{
    var entity = context.Entry(instance);
    entity.State = EntityState.Modified;        
    context.SaveChanges();
}

对GlobalExport 实例will automatically be detected even if its state is Detached 所做的任何更改。