ASP.在数据库中编辑CheckBoxList值
本文关键字：CheckBoxList 编辑 数据库 ASP | 更新日期: 2023-09-27 18:15:44
我很难理解如何在[HttpPost]编辑动作方法CustomerDeviceController上更新CheckBoxList值到我的数据库中的CustomerDevice表。
CustomerDeviceController的My Index Action Method显示客户表中的客户列表。我有一个ActionLink标签"编辑"传递CustId值CustomerDeviceController [HttpGet]编辑(int?id)的动作方法，然后显示所有选定的DevId值分配给CustId到CheckBoxList，这部分工作良好。
当我现在尝试更新CheckBoxList值时，我得到下面的错误消息。我被告知，在更新DevId值之前，我需要循环并删除它们。这是我不太明白的部分。
更新CheckBoxList时的错误信息
类型为'System '的异常。InvalidOperationException'在Microsoft.EntityFrameworkCore.dll中发生，但未在用户代码中处理
附加信息:无法跟踪实体类型'CustomerDevice'的实例，因为具有相同键的另一个该类型的实例已经被跟踪了。当添加新实体时，对于大多数键类型，如果没有设置键，将创建一个唯一的临时键值(即，如果为其类型分配了键属性的默认值)。如果您显式地为新实体设置键值，请确保它们不与现有实体或为其他新实体生成的临时值冲突。在附加现有实体时，确保只有一个具有给定键值的实体实例附加到上下文。
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 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; }
}
CustomerDeviceController
public ActionResult Create(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 = false //On the create view, no devices are selected by default
});
}
customervm.Devices = checkBoxListItems;
return View(customervm);
}
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(CustomerDeviceFormViewModel vm)
{
if (ModelState.IsValid)
{
foreach (var deviceId in vm.Devices.Where(x => x.IsChecked).Select(x => x.ID))
{
var customerDevices = new CustomerDevice
{
CustId = vm.CustId,
DevId = deviceId
};
db.CustomerDevices.Add(customerDevices);
}
db.SaveChanges();
return RedirectToAction("Index");
}
return View(vm);
}
public ActionResult Edit(int? id)
{
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);
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(CustomerDeviceFormViewModel vmEdit)
{
if (ModelState.IsValid)
{
Customer customer = db.Customers
.Include(c => c.CustomerDevices)
.SingleOrDefault(c => c.CustId == vmEdit.CustId);
if (customer == null)
{
return NotFound();
}
IEnumerable<int> selectedDevices = vmEdit.Devices.Where(x => x.IsChecked).Select(x => x.ID);
// Remove all selected devices for this customer
foreach (int removeId in selectedDevices)
{
customer.CustomerDevices.Clear();
}
// Add the new selected devices
foreach (int deviceId in selectedDevices)
{
CustomerDevice customerDevice = new CustomerDevice
{
CustId = customer.CustId,
DevId = deviceId
};
customer.CustomerDevices.Add(customerDevice);
}
// Update the customer
db.Customers.Update(customer); //or just db.Update(customer); same thing
// // Save and redirect
db.SaveChanges();
return RedirectToAction("Index");
}
return View(vmEdit);
}
编辑视图
<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>
共享/EditorTemplates 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 />
WebFormContext
public class WebFormContext : DbContext
{
public WebFormContext(DbContextOptions<WebFormContext> options)
: base(options)
{ }
public DbSet<Customer> Customers { get; set; }
public DbSet<State> States { get; set; }
public DbSet<Device> Devices { get; set; }
public DbSet<CustomerDevice> CustomerDevices { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Customer>()
.HasKey(c => c.CustId);
modelBuilder.Entity<Customer>()
.Property(c => c.CustDisplayName)
.HasColumnType("varchar(100)")
.HasMaxLength(100)
.IsRequired();
modelBuilder.Entity<Customer>()
.Property(c => c.CustFirstName)
.HasColumnType("varchar(50)")
.HasMaxLength(50);
modelBuilder.Entity<Customer>()
.Property(c => c.CustLastName)
.HasColumnType("varchar(50)")
.HasMaxLength(50);
modelBuilder.Entity<Customer>()
.Property(c => c.CustCompanyName)
.HasColumnType("varchar(50)")
.HasMaxLength(50);
modelBuilder.Entity<Customer>()
.Property(c => c.CustAddress)
.HasColumnType("varchar(100)")
.HasMaxLength(100)
.IsRequired();
modelBuilder.Entity<Customer>()
.Property(c => c.CustPhoneNumber)
.HasColumnType("varchar(12)")
.HasMaxLength(12);
modelBuilder.Entity<Customer>()
.Property(c => c.CustMobileNumber)
.HasColumnType("varchar(12)")
.HasMaxLength(12);
modelBuilder.Entity<Customer>()
.Property(c => c.CustEmailAddress)
.HasColumnType("varchar(320)")
.HasMaxLength(320);
modelBuilder.Entity<Device>()
.HasKey(d => d.DevId);
modelBuilder.Entity<Device>()
.Property(d => d.DevType)
.HasColumnType("varchar(50)")
.HasMaxLength(50)
.IsRequired();
modelBuilder.Entity<CustomerDevice>()
.HasKey(cd => new { cd.CustId, cd.DevId });
}
}
从我的理解来看，基本上你是在尝试做一个多对多的编辑。
首先你应该看看这个多对多。您需要像示例中那样更新您的模型，并在OnModelCreating方法中手动添加关系。另外，不要忘记在您的数据库上下文中为它添加DbSet。
在客户和设备模型中添加:
public List<CustomerDevice> CustomerDevices{ get; set; }
在WebFormContext OnModelCreating你应该有:
modelBuilder.Entity<CustomerDevice>()
.HasKey(c => new { c.CustId, c.DevId });
modelBuilder.Entity<CustomerDevice>()
.HasOne(cd => cd.Customer)
.WithMany(c => c.CustomerDevices)
.HasForeignKey(cd => cd.CustId);
modelBuilder.Entity<CustomerDevice>()
.HasOne(cd => cd.Device)
.WithMany(d => d.CustomerDevices)
.HasForeignKey(cd => cd.DevId);
之后，你可以使用include来加载相关的对象(例如，在Edit操作中):
Customer customer = db.Customers
.Include(c => c.CustomerDevices)
.SingleOrDefault(c => c.CustId == id);
那么您应该只对已分离的客户执行操作。
customer.CustomerDevices.Add(...);
customer.CustomerDevices.Remove(...);
//edit
然后将更改保存给客户
db.Customers.Update(customer);
db.SaveChanges();
在你的情况下，你可以这样做:
public ActionResult Edit(CustomerDeviceFormViewModel vmEdit)
{
if (ModelState.IsValid)
{
Customer customer = db.Customers
.Include(c => c.CustomerDevices)
.SingleOrDefault(c => c.CustId == id);
if (customer == null)
{
return NotFound();
}
IEnumerable<int> selectedDevices = vmEdit.Devices.Where(x => x.IsChecked).Select(x => x.ID);
// Add the new selected devices
foreach (int deviceId in selectedDevices)
{
var customerDevice = customer.CustomerDevices.FirstOrDefault(cd => cd.DevId == deviceId);
if(customerDevice != null)
{
customer.CustomerDevices.Remove(customerDevice);
}
else
{
CustomerDevice customerDevice = new CustomerDevice
{
CustId = customer.Id,
DevId = deviceId
};
customer.CustomerDevices.Add(customerDevice);
}
}
// Update the customer
db.Customers.Update(customer); //or just db.Update(customer); same thing
// Save and redirect
db.SaveChanges();
return RedirectToAction("Index");
}
return View(vmEdit);
}