MVC viewmodel Edit 在 Httppost 之后什么都不显示

Question

一段时间以来我一直在处理视图模型问题，我想解决一些问题。在我的视图模型中，我可以显示 "index" 并且可以添加新员工 "create"，但是 "Edit" 不起作用。

我可以显示 "edit" 页面，进行编辑（比如更改名称）但是当我 post 返回时，所有数据都显示为 null.在 "create" 中，在我 post 插入之后，控制器会显示更改 (EmployeeViewModel) 并插入记录。它只是不显示何时执行 "edit".

这是视图模型中固有的东西还是有其他东西？

这是我的视图模型class（数据库优先）：

public partial class Employee
    {
        public int EmployeeId { get; set; }
        public string Name { get; set; }
        public Nullable<int> DepartmentId { get; set; }
        public string Address { get; set; }

        public virtual Department Department { get; set; }
    }

 public partial class Department
    {
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
        public Department()
        {
            this.Employees = new HashSet<Employee>();
        }

        public int DepartmentId { get; set; }
        public string DepartmentName { get; set; }

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
        public virtual ICollection<Employee> Employees { get; set; }
    }

  public class EmployeeViewModel
    {
        public int EmployeeId { get; set; }
        public string Name { get; set; }
        public Nullable<int> DepartmentId { get; set; }
        public string Address { get; set; }
        public string DepartmentName { get; set; }

    }

这是我的控制器：

public class TestController : Controller
    {
        public  db dContext = new db();
        public ActionResult Index()
        {
            List<Employee> employeelist = dContext.Employees.ToList();
            EmployeeViewModel employeeVM = new EmployeeViewModel();

            List<EmployeeViewModel> employeeVMList = employeelist.Select(x => new EmployeeViewModel
            {
                Name = x.Name,
                EmployeeId = x.EmployeeId,
                Address = x.Address,
                DepartmentId = x.DepartmentId,
                DepartmentName = x.Department.DepartmentName
            }).ToList();
            return View(employeeVMList);    
        }
        public ActionResult Create()
        {
            return View();
        }
        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Create( EmployeeViewModel employeeVM)
        {
            if (ModelState.IsValid)
            {
                Employee e = new Employee();
                e.EmployeeId = employeeVM.EmployeeId;
                e.Name = employeeVM.Name;
                e.DepartmentId = employeeVM.DepartmentId;
                e.Address = employeeVM.Address;

                dContext.Employees.Add(e);
                dContext.SaveChanges();

                return RedirectToAction("Index");
            }
            return View("Index");
        } 

        public ActionResult Edit( EmployeeViewModel em , int? id)
        {
            var dbEmpVM = (from e in dContext.Employees
                           join d in dContext.Departments
                           on e.DepartmentId equals d.DepartmentId
                           where e.EmployeeId == id
                           select new EmployeeViewModel
                           {
                               EmployeeId = e.EmployeeId,
                               DepartmentId=e.DepartmentId,
                               Address=e.Address,
                               Name=e.Name,
                               DepartmentName=d.DepartmentName
                           }).ToList();      
             return View( dbEmpVM  );
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Edit(EmployeeViewModel model, int id)
        {
            string name = Request.Form["EmployeeId"];
            string naaanm = model.EmployeeId.ToString();

            return RedirectToAction("Index");
        }
    }

这是我的编辑：

@model  IEnumerable<MVCTutorial.Models.EmployeeViewModel>
@{
    ViewBag.Title = "Edit";
}
<h4>(EmployeeViewModel)</h4>
@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()

    foreach (var item in Model)
    {
<div class="form-group">
    @Html.LabelFor( i => item.EmployeeId, htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.EditorFor(i => item.EmployeeId, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(i => item.EmployeeId, "", new { @class = "text-danger" })
    </div>
</div>
<div class="form-group">
    @Html.LabelFor(i => item.Name, htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.EditorFor(i => item.Name, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(i => item.Name, "", new { @class = "text-danger" })
    </div>
</div>
<div class="form-group">
    @Html.LabelFor(i => item.DepartmentId, htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.EditorFor(i => item.DepartmentId, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(i => item.DepartmentId, "", new { @class = "text-danger" })
    </div>
</div>
        <div class="form-group">
            @Html.LabelFor(i => item.DepartmentName, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(i => item.DepartmentName, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(i => item.DepartmentName, "", new { @class = "text-danger" })
            </div>
        </div>
        <div class="form-group">
            @Html.LabelFor(i => item.Address, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(i => item.Address, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(i => item.Address, "", new { @class = "text-danger" })
            </div>
        </div>
    }
<div class="form-group">
    <div class="col-md-offset-2 col-md-10">
        <input type="submit" value="Edit" class="btn btn-default" />
    </div>
</div>
} 
<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

EmployeeViewModel

Answer 1

您当前的代码（在编辑视图中）将生成如下所示的输入标记。

<input class="form-control text-box single-line" 
        id="item_DepartmentName" name="item.DepartmentName" type="text" value="SomeName" />

查看名称属性值。是"item.DepartmentName"。您的 HttpPost 操作方法参数是 EmployeeViewModel 类型，但没有具有此名称的属性！因此，模型绑定器将无法将从您的表单中使用此名称 ("item.DepartmentName") 发布的表单数据映射到您的方法参数的任何属性。

解决方案是更新输入字段的 name 属性值以匹配 EmployeeViewModel 的属性名称。理想情况下，您的代码应生成如下标记。

<input name="DepartmentName" type="text" value="Some value" />

您可以在调用 html 帮助程序时明确指定 name 属性值。例如，使用 Html.TextBoxFor 助手

 @Html.TextBoxFor(i => item.DepartmentName, 
                               new  { @class = "form-control", NAME = "DepartmentName"  })

现在，当您提交表单时，模型绑定器将能够将该表单字段的值映射到您的 EmployeeViewModel 对象的 DepartmentName 属性。

MVC viewmodel Edit 在 Httppost 之后什么都不显示

MVC viewmodel Edit shows nothing after Httppost

asp.net-mvc-viewmodel