asp.net-mvc - HttpPost 上的模型为空

Question

这个让我完全莫名其妙...

我有一个非常简单的输入模型，具有三个字符串属性，如下所示:

public class SystemInputModel
{
    public string Name;
    public string Performance;
    public string Description;
}

在我的 Controller 中:

public ViewResult AddSystem()
{
    return View(new SystemInputModel());
}


[HttpPost]
public ActionResult AddSystem(SystemInputModel model) 
{
    if (ModelState.IsValid)
    {
        var system = new OasisSystem
        {
            Name = model.Name,
            Description = model.Description,
            Performance = model.Performance
        };
        return Json(repository.AddSystem(system));
    }
    return Json(new {success = false, message = "Internal error"});
}

View :

<h2>Add System</h2>

@using (Html.BeginForm())
{
    @Html.ValidationSummary(true)
    <label>Name</label>
    @Html.EditorFor(m => m.Name)
    <br />
    <label>Description</label>
    @Html.EditorFor(m => m.Description)
    <br />
    <label>Performance</label>
    @Html.EditorFor(m => m.Performance)
    <br />

    <input type="submit" />
}

我填写表单字段并点击提交。我看过 Fiddler 中的原始帖子:

POST http://localhost.:4772/System/AddSystem HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/x-ms-application, application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml+xml, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Referer: http://localhost.:4772/System/AddSystem
Accept-Language: en-us
Content-Type: application/x-www-form-urlencoded
UA-CPU: x86
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C; .NET4.0E; MS-RTC LM 8)
Connection: Keep-Alive
Content-Length: 42
Host: localhost.:4772
Pragma: no-cache
Cookie: ASP.NET_SessionId=5i4jtrrhjuujvtbpsju4bu3f

Name=foo&Description=bar&Performance=yes

但是，传递到我的 HttpPost Controller 方法中的模型的所有三个属性都为空值。如果我将它从我的模型对象更改为 FormCollection，我可以看到传入的三个属性。

为什么发布的字段没有映射到我的模型对象？

Answer 1

默认的 MVC 3 模型绑定(bind)器需要您模型上的属性。

如果您将模型更改为此:

public class SystemInputModel
{
    public string Name { get; set; }
    public string Performance { get; set; }
    public string Description { get; set; }
}

一切都会好的。