ASP.NET MVC 编辑数据库中的 CheckBoxList 值

Question

我无法理解如何根据 CustId 值从数据库中的 CustomerDevice 表中检索和编辑 DevId 值到 CheckBoxList。

CustomerDeviceController 的我的索引操作方法显示我的客户表中的客户列表。我有一个标有“Edit”的 ActionLink，它将 CustId 值传递给 CustomerDeviceController [HttpGet] Edit(int? id) Action Method，该方法当前显示 Devices 表中的所有 CheckBoxListItem 值。但是，CheckBoxList 不会显示从数据库中的 CustomerDevice 表到与 CustId 相关的 CheckBoxList 中检查的 DevId 值，而是显示对每个 CheckBoxList 值的检查。

我无法理解和弄清楚的部分是，如何根据 CustId 将数据库中 CustomerDevice 表中选定的 DevId 值显示到 CheckBoxList，然后在 [ HttpPost] 如果需要，将操作方法​​编辑回我的数据库中的 CustomerDevice 表。

请看下面我到目前为止的以下代码。

模型

public class CheckBoxListItem
{
    public int ID { get; set; }
    public string Display { get; set; }
    public bool IsChecked { get; set; }
}

public class Customer
{
    public int CustId { get; set; }
    public string CustDisplayName { get; set; }
    public string CustFirstName { get; set; }
    ....
}

public class Device
{
    public int DevId { get; set; }
    public string DevType { get; set; }
}

public class CustomerDevice
{
    public int CustId { get; set; }
    public int DevId { get; set; }
    public Customer Customer { get; set; }
    public Device Device { get; set; }
}

视图模型

public class CustomerDeviceFormViewModel
{
    public int CustId { get; set; }
    public string CustDisplayName { get; set; }
    public List<CheckBoxListItem> Devices { get; set; }
}

客户设备控制器

public ActionResult Edit(int? id)
{
    if (id == null)
    {
        return NotFound();
    }
    var customervm = new CustomerDeviceFormViewModel();
    Customer customer = db.Customers.SingleOrDefault(c => c.CustId == id);
    if (customer == null)
    {
        return NotFound();
    }
    customervm.CustId = customer.CustId;
    customervm.CustDisplayName = customer.CustDisplayName;
    // Retrieves list of Devices for CheckBoxList
    var deviceList = db.Devices.ToList();
    var checkBoxListItems = new List<CheckBoxListItem>();
    foreach (var device in deviceList)
    {
        checkBoxListItems.Add(new CheckBoxListItem()
        {
            ID = device.DevId,
            Display = device.DevType,
            IsChecked = deviceList.Where(x => x.DevId == device.DevId).Any()
        });
    }
    customervm.Devices = checkBoxListItems;
    return View(customervm);
}

        [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Edit(CustomerDeviceFormViewModel vmEdit)
    {
        if (ModelState.IsValid)
        {
            Customer customer = db.Customers.SingleOrDefault(c => c.CustId == vmEdit.CustId);

            if (customer == null)
            {
                return NotFound();
            }

            foreach (var deviceId in vmEdit.Devices.Where(x => x.IsChecked).Select(x => x.ID))
            {
                var customerDevices = new CustomerDevice
                {
                    CustId = vmEdit.CustId,
                    DevId = deviceId
                };

                db.Entry(customerDevices).State = EntityState.Modified;
            }

            db.SaveChanges();
            return RedirectToAction("Index");
        }

        return View(vmEdit);
    }

Edit.chtml

<div class="form-group">
    Please select the Devices to assign to <b>@Html.DisplayFor(c => c.CustDisplayName)</b>
</div>

<div class="form-group">
    @Html.EditorFor(x => x.Devices)
</div>

@Html.HiddenFor(c => c.CustId)

<div class="form-group">
    <button type="submit" class="btn btn-primary">Submit</button>
</div>

Shared/EditorTemplate/CheckBoxListItem.chtml

<div class="checkbox">
<label>
    @Html.HiddenFor(x => x.ID)
    @Html.CheckBoxFor(x => x.IsChecked)
    @Html.LabelFor(x => x.IsChecked, Model.Display)
</label>
<br />

Answer 1

您用于设置IsChecked 值的代码将始终返回true（您的循环基本上是说如果集合包含我（当然它包含）然后将其设置为true）。

您需要通过读取CustomerDevice 表中的值来获取每个Customer 的选定值

Customer customer = db.Customers.SingleOrDefault(c => c.CustId == id);
if (customer == null)
{
    return NotFound();
}
// Get all devices
var deviceList = db.Devices.ToList();
// Get the selected device ID's for the customer
IEnumerable<int> selectedDevices = db.CustomerDevices
    .Where(x => x.CustId == id).Select(x => x.DevId);
// Build view model
var model = new CustomerDeviceFormViewModel()
{
    CustId = customer.CustId,
    CustDisplayName = customer.CustDisplayName,
    Devices = deviceList.Select(x => new CheckBoxListItem()
    {
        ID = x.DevId,
        Display = x.DevType,
        IsChecked = selectedDevices.Contains(x.DevId)
    }).ToList()
};
return View(model);

Answer 2

这是我使用的 Razor 代码的 sn-p：

   foreach (SelectListItem p in Model.PositionList)
    {
    @Html.Raw(p.Text + "<input type=checkbox name=\"PositionIDs\" id=\"PositionIDs\" value=" + @p.Value + (Model.Positions != null && Model.Positions.Any(pos => pos.ScoreCardId == Convert.ToInt32(p.Value)) ? " checked />" : " />"));
    }

Answer 3

您可能想看看 MvcCheckBoxList NuGet 包：

https://www.nuget.org/packages/MvcCheckBoxList/

这使得在 MVC 中使用 CheckBoxList 做一些强大的事情变得更加容易 - 并且可能是解决 CheckBox 问题的更好方法。