在 ASP.NET Core MVC 中实例化和初始化模型的最佳实践答案

【问题标题】：Best practice for instantiating and initialising a Model in ASP.NET Core MVC在 ASP.NET Core MVC 中实例化和初始化模型的最佳实践
【发布时间】：2019-10-15 22:01:38
【问题描述】：

我有一个返回视图的方法，在该视图中我想显示一些东西的列表。为了做到这一点，我需要一个带有房屋列表的模型。

Microsoft 的文档 (https://docs.microsoft.com/en-us/aspnet/core/mvc/overview?view=aspnetcore-2.2) 指出，选择和使用模型是控制器的责任，而模型的责任是封装业务逻辑。话虽如此，我不确定最佳做法：

控制器中的逻辑：

型号：

public class DepartmentViewModel
{
    public IEnumerable<DepartmentDto> lstDepartments { get; set; }
}

控制器：

public class DepartmentController : Controller
{
    private readonly IUnitOfWork _work;
    private readonly IMapper _mapper;

    public DepartmentController(IUnitOfWork work, IMapper mapper)
    {
        _work = work;
        _mapper = mapper;
    }

    public async Task<IActionResult> Index(DepartmentViewModel viewmodel)
    {
        var lstAllDepartments = _work.DepartmentRepository.GetAll(); // All departments from the database.
        var lstDepartmentsForViewmodel = _mapper.Map<IEnumerable<Core.Entities.Department>, IEnumerable<DepartmentDto>>(lstAllDepartments); // Map to DTO.
        viewmodel.lstDepartments = lstDepartmentsForViewmodel;
        return View(viewmodel);
    }
}

模型中的逻辑：

型号：

public class DepartmentViewModel
{
    private readonly IUnitOfWork _work;
    private readonly IMapper _mapper;

    public DepartmentViewModel(IUnitOfWork work, IMapper mapper)
    {
        _work = work;
        _mapper = mapper;
        var lstAllDepartments = _work.DepartmentRepository.GetAll(); // All departments from the database.
        var lstDepartmentsForViewmodel = _mapper.Map<IEnumerable<Core.Entities.Department>, IEnumerable<DepartmentDto>>(lstAllDepartments); // Map to DTO.
        lstDepartments = lstDepartmentsForViewmodel;
    }

    public IEnumerable<DepartmentDto> lstDepartments { get; set; }
}

控制器：

public class DepartmentController : Controller
{
    private readonly IUnitOfWork _work;
    private readonly IMapper _mapper;

    public DepartmentController(IUnitOfWork work, IMapper mapper)
    {
        _work = work;
        _mapper = mapper;
    }

    public async Task<IActionResult> Index()
    {
        DepartmentViewModel viewmodel = new DepartmentViewModel(_work, _mapper);
        return View(viewmodel);
    }
}

任何形式的指导将不胜感激。

【问题讨论】：

标签： c# json asp.net-core .net-core asp.net-core-mvc

【解决方案1】：

我建议你选择第一种方法

控制器中的逻辑：

型号：

public class DepartmentViewModel
{
    public IEnumerable<DepartmentDto> lstDepartments { get; set; }
}

控制器：

public class DepartmentController : Controller
{
    private readonly IUnitOfWork _work;
    private readonly IMapper _mapper;

    public DepartmentController(IUnitOfWork work, IMapper mapper)
    {
        _work = work;
        _mapper = mapper;
    }

    public async Task<IActionResult> Index(DepartmentViewModel viewmodel)
    {
        var lstAllDepartments = _work.DepartmentRepository.GetAll(); // All departments from the database.
        var lstDepartmentsForViewmodel = _mapper.Map<IEnumerable<Core.Entities.Department>, IEnumerable<DepartmentDto>>(lstAllDepartments); // Map to DTO.
        viewmodel.lstDepartments = lstDepartmentsForViewmodel;
        return View(viewmodel);
    }
}

最佳实践是使用 DI 在构造函数中初始化服务或依赖项值。如果您采用第二种方法，则必须像这样将数据发送到构造函数

DepartmentViewModel viewmodel = new DepartmentViewModel(_work, _mapper);

如果你有很多模型，那不是理想的情况？

【讨论】：