asp.net-core - 从视图模型更新时隐藏字段的任何替代方法？我不想在编辑页面中包含所有字段

Question

我知道有一种方法可以“正确”地做到这一点，但由于某种原因我找不到答案。我什至在微软的指南上看到隐藏字段是要走的路，但感觉“错误”。

当我将所有隐藏字段放入编辑表单时，我发现我的更新工作正常：

    <input type="hidden" asp-for="OrgUnits.Organizations" />
    <input type="hidden" asp-for="OrgUnits.Address" />
    <input type="hidden" asp-for="OrgUnits.AlternateId" />
    <input type="hidden" asp-for="OrgUnits.Category" />
    <input type="hidden" asp-for="OrgUnits.City" />
    <input type="hidden" asp-for="OrgUnits.FriendlyPath" />
    <input type="hidden" asp-for="OrgUnits.IsTop" />
    <input type="hidden" asp-for="OrgUnits.Name" />
    <input type="hidden" asp-for="OrgUnits.NextChildId" />
    <input type="hidden" asp-for="OrgUnits.RecoveryOverride" />
    <input type="hidden" asp-for="OrgUnits.RowStatus" />
    <input type="hidden" asp-for="OrgUnits.RowVersion" />
    <input type="hidden" asp-for="OrgUnits.State" />
    <input type="hidden" asp-for="OrgUnits.UseAppVersion" />
    <input type="hidden" asp-for="OrgUnits.ZipCode" />

但是，这似乎是一种糟糕的代码编写方式。我只希望此表中的一些字段是可编辑的。

这是我的控制器：

    public async Task<IActionResult> Edit(string id, [Bind("OrgUnits")] OrgUnitsViewModel orgUnitsViewModel)
    {
        id = Uri.UnescapeDataString(id);
        
        if (id != orgUnitsViewModel.OrgUnits.OrgUnitId)
        {
            return NotFound();
        }

        if (ModelState.IsValid)
        {
            try
            {
                //Get org for the DbCatalog
                var org = await _opkCoreContext.Organizations.FindAsync(orgUnitsViewModel.OrgUnits.OrgId);
                _serverConnectionHelper.SetDatabaseConnectStringToSession(org.DbCatalog);

                _opkDataContext.Update(orgUnitsViewModel.OrgUnits);
                await _opkDataContext.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!OrgUnitsExists(orgUnitsViewModel.OrgUnits.OrgUnitId))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }
            return RedirectToAction(nameof(Index), new { currentSearchFilter = orgUnitsViewModel.OrgUnits.OrgUnitId });
        }
        return View(orgUnitsViewModel);
    }

这真的是应该怎么做的。我走了 AutoMapper 的路线，但这对我来说失败了，我不太明白如何使用它。无论如何，这是我的错误：

DbUpdateConcurrencyException: Database operation expected to affect 1 row(s) but actually affected 0 row(s). Data may have been modified or deleted since entities were loaded. 

希望你们中的一个聪明人知道答案。我很惊讶我在 Google 或 SO 上找不到任何东西，因为我知道这非常普遍。只是隐藏的苍蝇看起来很不对劲，因为如果你错过了怎么办？

非常感谢您提前。

标签： asp.net-coreautomapperasp.net-core-3.1ef-core-3.0ef-core-3.1

Answer 1

我个人执行以下操作以部分更新实体：

如果我不想将整个模型发送到操作以更改整个实体，我会创建一个端点（API 操作）来部分更新实体并返回成功状态代码而不是 View。我会使用对端点的 ajax 请求来更改实体而不刷新页面。

这是我部分更新Employee实体的代码：

员工.cs

public class Employee
{
    public int Id { get; set; }

    [Required(ErrorMessage ="Employee name is a required field.")]
    [MaxLength(30,ErrorMessage ="Maximum length for the Name is 30 chrachters.")]
    public string Name { get; set; }

    [Required(ErrorMessage = "Age is a required field.")]
    public int Age{ get; set; }

    [Required(ErrorMessage = "Position is a required field.")]
    [MaxLength(20, ErrorMessage = "Maximum length for the Position is 20 chrachters.")]
    public string Position { get; set; }


    public int CompanyId { get; set; }
    public Company Company { get; set; }
}

EmployeeUpdateDto.cs

public class EmployeeUpdateDto
{
    [Required(ErrorMessage = "Employee name is required")]
    [MaxLength(30, ErrorMessage = "Maximum length for the Name is 30 characters")]
    public string Name { get; set; }

    [Range(18, int.MaxValue, ErrorMessage = "Minimum age must be 18")]
    public int Age { get; set; }

    [Required(ErrorMessage = "Employee position is required")]
    [MaxLength(20, ErrorMessage = "Maximum length for the Position is 20 characters")]
    public string Position { get; set; }
}

控制器.cs

public class EmployeesController : ControllerBase
{
    private IRepositoryManager _repository;
    private ILoggerManager _logger;
    private IMapper _mapper;

    public EmployeesController(IRepositoryManager repository, ILoggerManager logger, IMapper mapper)
    {
        _repository = repository;
        _logger = logger;
        _mapper = mapper;
    }


    [HttpPatch("{id}")]
    public async Task<IActionResult> PartiallyUpdateEmployee(int id, JsonPatchDocument<EmployeeUpdateDto> employeePatches)
    {
        if (employeePatches is null)
        {
            _logger.LogError("JsonPatchDocument object sent from client is null");
            return BadRequest();
        }

        var employeeEntity = await _repository.EmployeeRepository.GetEmployeeAsync(employeeId, trackChanges:true);
        if (employeeEntity null)
        {
            _logger.LogInfo($"Employee with id {id} doesn't exist in the database.");
            return NotFound();

        }

        var employeeUpdateDto = _mapper.Map<EmployeeUpdateDto>(employeeEntity);

        employeePatches.ApplyTo(employeeUpdateDto, ModelState);
        TryValidateModel(employeeUpdateDto);

        if (!ModelState.IsValid)
        {
            _logger.LogError("invalid model state for the patch document");
            return UnprocessableEntity(ModelState);
        }

        _mapper.Map(employeeUpdateDto, employeeEntity);
        await _repository.SaveAsync();

        return NoContent();
    }

    //other action methods

}

您必须以以下标准补丁格式 (json) 发送请求正文：

[ 
  { "op": "replace", "path": "/name", "new_name": "new name" }, 
  { "op": "remove", "path": "/position" } 
]

而已。上面的示例请求会将 Employee 名称更改为“new_name”，并将 Position 设置为其默认值（在本例中为 null）。

上面的示例需要这些先决条件才能工作：

• Microsoft.AspNetCore.JsonPatch支持JsonPatchDocument类型。

• Microsoft.AspNetCore.Mvc.NewtonsoftJson支持映射请求到JsonPatchDocument<T>. 在方法中配置它ConfigureServices()：

  services.AddControllersWithViews .AddNewtonsoftJson();

• AutoMapper.Extensions.Microsoft.DependencyInjection将 EmployeeUpdateDto 映射到 Employee。添加映射配置文件类并在ConfigureServices()方法中配置 AutoMapper：

  services.AddAutoMapper(typeof(Startup));
  

和

public class MappingpProfile : Profile
{
    public MappingpProfile()
    {
        CreateMap<CompanyUpdateDto, Company>();
        CreateMap<CompanyCreationDto, Company>();

        CreateMap<Employee, EmployeeDto>();
        CreateMap<EmployeeCreationDto, Employee>();
        CreateMap<EmployeeUpdateDto, Employee>().ReverseMap();
    }
}

在上面的代码中，我们使用CreateMap<EmployeeUpdateDto, Employee>().ReverseMap();我们的需要。