ASP.NET MVC 使用 ViewModel 创建、编辑和删除

本文关键字：编辑 删除 创建 ViewModel NET MVC 使用 ASP | 更新日期: 2023-09-27 17:56:37

无论出于何种原因，我都无法使用我创建的名为CreateEmployeeViewModel的ViewModel进行创建和编辑。但是，我可以在不使用CreateEmployeeViewModel的情况下创建和编辑，但是被告知使用CRUD的主要模型是不好的。但是，我能够使用CreateEmployeeViewModel很好地检索到我的2个DropDownList标签的值，而不是创建或编辑。 以下是我当前的模型，视图模型，控制器和视图。

我

只是弄清楚为什么我不能使用 public IActionResult Create(Employee employee) 活动方法创建。

员工模型：（位于"模型"文件夹中）

    public class Employee
{
    [Key]
    public int EmpId { get; set; }
    [Required]
    public string EmpFirstName { get; set; }
    [Required]
    public string EmpLastName { get; set; }
    public int DeptId { get; set; }
    public Department Department { get; set; }
    public int BldgId { get; set; }
    public Building Building { get; set; }
}

员工控制器：（位于控制器文件夹中）

public class EmployeeController : Controller
{
    private DataEntryContext _context;
    public EmployeeController(DataEntryContext context)
    {
        _context = context;
    }
    public IActionResult Index()
    {
        return View(_context.Employees.ToList());
    }
    // Populate Department values to DropDownList
    private IEnumerable<SelectListItem> GetDeptList()
    {
        var dept = _context.Departments
            .Select(s => new SelectListItem
            {
                Value = s.DeptId.ToString(),
                Text = s.DeptTitle
            })
            .ToList();
        return (dept);
    }
    // Populate Building values to DropDownList
    private IEnumerable<SelectListItem> GetBldgList()
    {
        var bldg = _context.Buildings
            .Select(b => new SelectListItem
            {
                Value = b.BldgId.ToString(),
                Text = b.BldgName
            })
            .ToList();
        return (bldg);
    }
    public IActionResult Create()
    {
        CreateEmployeeViewModel model = new CreateEmployeeViewModel();
        model.DeptList = GetDeptList();
        model.BldgList = GetBldgList();
        return View(model);
    }
    [HttpPost]
    [ValidateAntiForgeryToken]
    public IActionResult Create(Employee employee)
    {
        if (ModelState.IsValid)
        {
            _context.Employees.Add(employee);
            _context.SaveChanges();
            return RedirectToAction("Index");
        }
        return View(employee);
    }
    public IActionResult Edit(int? id)
    {
        if (id == null)
        {
            return View("Error");
            //return NotFound();
        }
        var employee = _context.Employees
            .Where(e => e.EmpId == id)
            .Single();
        if (employee == null)
        {
            return View("Error");
            //return NotFound();
        }
        return View(employee);
    }
    [HttpPost]
    [ValidateAntiForgeryToken]
    public IActionResult Edit(Employee employee)
    {
        if (ModelState.IsValid)
        {
            _context.Employees.Update(employee);
            _context.SaveChanges();
           return RedirectToAction("Index");
        }
        return View(employee);
    }
}

CreateEmployeeViewModel：（位于ViewModels文件夹中）

    public class CreateEmployeeViewModel
{
    public int EmpId { get; set; }
    public string EmpFirstName { get; set; }
    public string EmpLastName { get; set; }

    public int DeptId { get; set; }
    public IEnumerable<SelectListItem> DeptList { get; set; }

    public int BldgId { get; set; }
    public IEnumerable<SelectListItem> BldgList { get; set; }
}

员工创建视图：

<form asp-controller="employee" asp-action="Create" method="post" class="form-horizontal" role="form">
<div class="form-horizontal">
    <div asp-validation-summary="All" class="text-danger"></div>
    <div class="form-group">
        <label asp-for="EmpFirstName" class="col-md-2 control-label">First Name</label>
        <div class="col-md-10">
            <input asp-for="EmpFirstName" class="form-control" />
            <span asp-validation-for="EmpFirstName" class="text-danger"></span>
        </div>
    </div>
    <div class="form-group">
        <label asp-for="EmpLastName" class="col-md-2 control-label">Last Name</label>
        <div class="col-md-10">
            <input asp-for="EmpLastName" class="form-control" />
            <span asp-validation-for="EmpLastName" class="text-danger"></span>
        </div>
    </div>
    <div class="form-group">
        <label asp-for="DeptId" class="col-md-2 control-label">Department</label>
        <div class="col-md-10">  
            <select asp-for="DeptId" asp-items="@Model.DeptList" class="form-control">
                <option>Select Department</option>
            </select>
            <span asp-validation-for="DeptId" class="text-danger"></span>
        </div>
    </div>
    <div class="form-group">
        <label asp-for="BldgId" class="col-md-2 control-label">Building Location</label>
        <div class="col-md-10">
            <select asp-for="BldgId" asp-items="@Model.BldgList" class="form-control">
                <option>Select Building</option>
            </select>
            <span asp-validation-for="BldgId" class="text-danger"></span>
        </div>
    </div>
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Create" class="btn btn-default" />
        </div>
    </div>
</div>

ASP.NET MVC 使用 ViewModel 创建、编辑和删除

在 Create 方法中，您将 CreateEmployeeViewModel 发送到

视图，但在 HttpPost Create 方法中，您接受的是 Employee 模型而不是 CreateEmployeeViewModel。因此，一旦更改了发布方法签名以接受正确的 CreateEmployeeViewModel，您就可以简单地将其映射回员工模型。

获取操作方法：

public IActionResult Create(Employee employee)
{
    return View(employee);
}

只需更改您的Post Action Method：

[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult Create(CreateEmployeeViewModel vm)
{
    if (ModelState.IsValid)
    {
var model = new Employee{
   //your logic here for example
    employeename = vm.employeename,
    employeepassword = vm.employeepassword
   } 
        _context.Employees.Add(model);
        _context.SaveChanges();
        return RedirectToAction("Index");
    }
    return View(employee);
}

并且不要忘记在您的.cshtml中计算视图模型

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