将 Html.CheckBoxFor 的几个复选框值返回给控制器

Question

我有一个视图，用户应该通过复选框选择几个列出的项目，然后应该在控制器中工作。

但是，我没有将值传递给控制器​​的 POST 方法；调试时 List 为 null。

在搜索答案时，我找不到与 C# 匹配的一个和多个值的 Html.CheckboxFor。

我觉得这可能只是一个小问题，但我现在几天都想不通。

这是我的模型：

public class ShownListofTools// This List is given to the View to contain all Tools
{
    public IEnumerable<CheckboxItem> ToolsInShownList { get; set; } = new List<CheckboxItem>();         
}

public  class CheckboxItem //This Model is used to bring the Tools to the View
{
    public int ShownToolID { get; set; }
    public bool IsChecked { get; set; }
    public string DisplayName { get; set; }
    public int RemainingWorkTime { get; set; }
}

这是控制器：

[HttpGet]
public ActionResult IndexforLend()
{
        // 1)
        var notwornouttools = db.Tools.Where(t => t.Max_Worktime - t.CurrentWorktime > 0); // List Tools that are not worn out yet
        var tools = notwornouttools.Where(t => t.UserID == null);  //refine Filter to all tools that are currently not lent by other users                                                                          
        // 2)
        List<CheckboxItem> SelectListTools = new List<CheckboxItem>(); //temporary list, to gather all needed items

        // 3)
        foreach(var item in tools)//work down the "tool" list from above
        {
            SelectListTools.Add(
                new CheckboxItem()//Add a new Checkbox Item
                {
                     DisplayName = item.Tooltype + " " + item.Diameter+"mm", //Transfer the Attributes from the "tool" list
                     ShownToolID = item.ID,
                    IsChecked = false,
                    RemainingWorkTime = item.Max_Worktime - item.CurrentWorktime,
                }
             );
        }

        //Checkboxlist.ToolsInShownList = SelectListTools; //The Checkbox Items are Added to the List "Checkboxlist".
        return View(SelectListTools); // The List "Checkboxlist" is transferred to the View.
}               

//POST: Add Tools to a User
[HttpPost]
public ActionResult IndexforLend([Bind(Include = "IsChecked,ShownToolID")] List<CheckboxItem> chklist)  //import from View, but make it numerable         
{            
    foreach(var item in chklist) //go through the entire Checkboxlist
    {
        if (item.IsChecked == true) // if the Checkbox was Checked - not sure if only checked objects are returned
        {
            var id = item.ShownToolID; // take the Tool-ID to the variable "id"

            foreach(var realtool in db.Tools) //go through all Tools in Database
            {
                if (realtool.ID == id) // if the Id from the Checkbox is found
                {
                    realtool.UserID = LoggedInUser.ID; // set the Foreign Key UserID to the ID of the Logged in User
                    db.Entry(realtool).State = EntityState.Modified;
                    db.SaveChanges();
                }
            }
        };
    }

    return RedirectToAction("Index");
}

观点：

@model  List<WZ_Web2.Models.CheckboxItem>
   <p></p> 
<p></p>
<div>Please select the Tools you want to lend:</div>

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()
       <table class="table">
           @**@
        <tr>
            <th>
                Select
            </th>
            <th>
                Tool Name
            </th>
            <th>
                Remaining Work Time
            </th>                      
        </tr>

        @foreach (var item in Model)
        {
           <tr>
               <td>
                   @Html.CheckBoxFor(modelItem => item.IsChecked)
                   @Html.HiddenFor(modelItem => item.ShownToolID)

               </td>
               <td>
                   @Html.DisplayFor(modelItem => item.DisplayName)
               </td>              
               <td>
                   @Html.DisplayFor(modelItem => item.RemainingWorkTime)
               </td>

           </tr>
        }
    </table>
    <div class="col-md-offset-2 col-md-10">
        <input type="submit" value="submit" class="btn btn-default" />        
    </div>
}

Answer 1

使用foreach 这样它不会在帖子中生成索引名称列表。当您通过item 进行迭代并设置modelItem 时，它会在帖子中生成类似这样的内容：

item.IsChecked=true&item.ShownToolID=1&item.IsChecked=false&item.ShownToolID=2...

但控制器期待一个索引列表，例如：

[0].IsChecked=true&[0].ShownToolID=1&[1].IsChecked=false&[1].ShownToolID=2...

因此，mapper 无法绑定您帖子中的数据。我通过检查帖子发现了。尝试改用for...

在你看来：

@for (int i = 0; i < Model.Count; i++ )
{
    <tr>
        <td>
            @Html.CheckBoxFor(item => Model[i].IsChecked)
            @Html.HiddenFor(item => Model[i].ShownToolID)

        </td>
        <td>
            @Html.DisplayFor(item => Model[i].DisplayName)
        </td>
        <td>
            @Html.DisplayFor(item => Model[i].RemainingWorkTime)
        </td>

    </tr>
}

在您的控制器中：

[HttpPost]
public ActionResult IndexforLend(List<CheckboxItem> chklist)