下拉菜单，造成无效的模型状态。 ASP.NET MVC 3 [英] Drop-Down Menu Causing Invalid Model State. ASP.NET MVC 3

问题描述

我在我的web应用程序的注册视图。然而，帐号注册将不会成功，我的下拉菜单中会以红色列出。

I have a registration view in my web app. However, account registration would be unsuccessful and my drop-down menu would be outlined in red.

下面是我的下拉code：

Here is my drop down code:

<div class="editor-label">  
   @Html.LabelFor(model => model.CompanyId, "Company")  
</div>   
<div class="editor-field">  
   @Html.DropDownList("Companies", "<Select Company>")  
</div>

下面是我的相关code。在视图模型：

Here is my associated code in the view model:

[Display(Name = "Company")]    
public int? CompanyId { get; set; }

public IEnumerable<SelectListItem> Companies { get; set; }

下面是在控制器我相关的code才返回的观点：

Here is my associated code in the controller before I return the view:

ViewBag.Companies = new SelectList(db.Companies, "CompanyId", "CompanyName");

当我调试，我发现 ModelState.IsValid 返回false，因此重新返回视图（并重新设置 ViewBag.Companies在我的情况）。

As I debug, I find that ModelState.IsValid returns false, and therefore re-returns the view (and re-sets ViewBag.Companies in my case).

我如何成功完成注册？我的参数范围内填写每个必填字段。它不要求选择的公司。 ：当我不选择一个公司， ModelState.IsValid 返回true，并通过code运行。不过，我想用户必须与他的公司相关联的选项。

How do I complete a successful registration? I do fill out each required field within parameters. It is not required to select company. When I do not select a company, ModelState.IsValid returns true and runs through the code. However, I would like the user to have the option to associate with his company.

感谢。

推荐答案

为什么你会需要在设置 ViewBag.Companies ，当你有更好的方法 - 有选择列出到模型？无需使用难看ViewBag

Why would you need setting ViewBag.Companies, when you've got the better approach - having select list into the model? No need to use ugly ViewBag

您应该有这样的事情

视图模型

public class RegisterViewModel
{
     [Display(Name = "Company")]    
     public int? CompanyId { get; set; }

     public IEnumerable<SelectListItem> Companies { get; set; }
}

控制器

[HttpGet]
public ActionResult Register()
{
     RegisterViewModel viewModel = new RegisterViewModel();
     viewModel.Companies = new SelectList(db.Companies, "CompanyId", "CompanyName");

     return View(viewModel);
}

和视图

<div class="editor-label">  
   @Html.LabelFor(model => model.CompanyId, "Company")  
</div>   
<div class="editor-field">  
   @Html.DropDownListFor(model => model.CompanyId, Model.Companies, "<Select Company>")  
</div>

这将绑定你的 CompanyId 在服务器上正确。

This will bind your CompanyId on server correctly.

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