将信息从循环创建的表单发布到控制器 MVC

Question

在视图中有一个 for 循环，它生成 4 个表单，只有一个提交按钮，当单击该按钮时，表单中的每个条目都会被发布。

在我的 HttpPost 控制器中，我执行了以下操作：

[HttpPost]
public ActionResult Index(List<ForTestingOnly> receivedData)
    {
receivedData.ForEach(delegate (ForTestingOnly data)
        {

            get_Description += data.Description + ", ";
            get_Name += data.Name + ", ";

        });
        ViewData["P_Description"] = get_Description;
        ViewData["P_Name"] = get_Name;
        return View();
}

我收到以下错误：

用户代码未处理 NullReferenceException MVC_Application.dll 中出现“System.NullReferenceException”类型的异常，但未在用户代码中处理。 附加信息：对象引用未设置为对象的实例。

我尝试了另一种方法：

  [HttpPost]
    public ActionResult Index(List<ForTestingOnly> receivedData)
    {
foreach (ForTestingOnly data in receivedData)
        {
            get_Description += data.Description + ", ";
            get_Name += data.Name + ", ";
        }
        ViewData["P_Description"] = get_Description;
        ViewData["P_Name"] = get_Name;
        return View();
}

我再次收到以下错误：

用户代码未处理 NullReferenceException MVC_Application.dll 中出现“System.NullReferenceException”类型的异常，但未在用户代码中处理。 附加信息：对象引用未设置为对象的实例。

之后我在 HttpPost 控制器中添加了以下内容：

receivedData = new List<ForTestingOnly>();

添加上面的代码后，错误信息消失了。但是，当我在单击提交按钮后尝试在视图的文本框中显示输入的数据时，什么都没有出现。

下面是模型和视图：

型号：

   public class ForTestingOnly
{
     [Display(Name = "Description: ")]
    [Required(ErrorMessage = "The description of the sub event is required.")]
    public string Description { get; set; }

    [Display(Name = "Name: ")]
    [Required(ErrorMessage = "The name is required.")]
    public string Name { get; set; }
}

查看：

@{
Layout = "~/Views/Shared/_Layout.cshtml";
}
<br />
<h4>Count: @ViewData["Count"]</h4>
<br />
<h4>Posted Description: @ViewData["P_Description"]</h4>
<br />
<h4>Posted Name: @ViewData["P_Name"]</h4>
<br />
@using (Html.BeginForm()) 
{
 @Html.AntiForgeryToken()

<div class="form-horizontal">
    <hr />
    @for(int counter = 0; counter<2; counter++) { 
        <h5>Form: @(counter + 1)</h5>
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    <div class="form-group">
        @Html.LabelFor(model => model.Description, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Description, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Description, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Name, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.Name, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.Name, "", new { @class = "text-danger" })
        </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>
}

Answer 1

像这样更改你的模型标签

@Html.EditorFor(model => model[counter].Name, new { htmlAttributes = new { @class = "form-control" } })