我在寻找一个教程/视频,展示如何使用EntityFramework从数据库中实现级联下拉列表。我正在使用ASP.NET MVC Core,EntityFramework Core和C#。
目前,我能够成功地从我的数据库中检索数据到三个下拉列表中。
我想要实现的是,用户首先选择一个州,然后显示所有与该州相关的城市。然后,当用户选择了一个城市后,它将显示与该城市相关的邮政编码。
任何帮助都将不胜感激。 模型
目前,我能够成功地从我的数据库中检索数据到三个下拉列表中。
我想要实现的是,用户首先选择一个州,然后显示所有与该州相关的城市。然后,当用户选择了一个城市后,它将显示与该城市相关的邮政编码。
任何帮助都将不胜感激。 模型
public class Customer
{
public int CustomerId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public int StateId { get; set; }
public int CityId { get; set; }
public int ZipId { get; set; }
public State State { get; set; }
public City City { get; set; }
public Zip Zip { get; set; }
}
public class State
{
public int StateId { get; set; }
public string Abbr { get; set; }
public List<Customer> Customers { get; set; }
}
public class City
{
public int CityId { get; set; }
public string Name { get; set; }
public int StateId { get; set; }
public State State { get; set; }
public List<Customer> Customers { get; set; }
}
public class Zip
{
public int ZipId { get; set; }
public string PostalCode { get; set; }
public int CityId { get; set; }
public City City { get; set; }
public List<Customer> Customers { get; set; }
}
ViewModels
public class CustomerFormVM
{
public int CustomerId { get; set; }
[Display(Name = "First Name")]
[StringLength(50)]
public string FirstName { get; set; }
[Display(Name = "Last Name")]
[StringLength(50)]
public string LastName { get; set; }
[Required(ErrorMessage = "Select State")]
[Display(Name = "State")]
public int StateId { get; set; }
//public IEnumerable<State> States { get; set; }
public IEnumerable<SelectListItem> States { get; set; }
[Required(ErrorMessage = "Select City")]
[Display(Name = "City")]
public int CityId { get; set; }
//public IEnumerable<City> Citys { get; set; }
public IEnumerable<SelectListItem> Citys { get; set; }
[Required(ErrorMessage = "Select Zip")]
[Display(Name = "Zip")]
public int ZipId { get; set; }
//public IEnumerable<Zip> Zips { get; set; }
public IEnumerable<SelectListItem> Zips { get; set; }
}
客户控制器
public class CustomerController : Controller
{
private MultiDbContext db;
public CustomerController(MultiDbContext context)
{
db = context;
}
// GET: /<controller>/
public IActionResult Index()
{
return View(db.Customers.ToList());
}
public IActionResult getCititesFromDatabaseByStateId(int id)
{
return View(db.Citys.Where(c => c.StateId == id).ToList());
}
public IActionResult getCities(int id)
{
var cities = new List<City>();
cities = getCititesFromDatabaseByStateId(id); //call repository
return Json(cities);
}
public ActionResult Create()
{
var states = db.States.ToList();
var citys = db.Citys.ToList();
var zips = db.Zips.ToList();
var viewModel = new CustomerFormVM
{
States = states,
Citys = citys,
Zips = zips
};
return View(viewModel);
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(CustomerFormVM vm)
{
if (ModelState.IsValid)
{
var customer = new Customer();
{
customer.FirstName = vm.FirstName;
customer.LastName = vm.LastName;
customer.StateId = vm.StateId;
customer.CityId = vm.CityId;
customer.ZipId = vm.ZipId;
}
db.Customers.Add(customer);
db.SaveChanges();
return RedirectToAction("Index");
}
else
{
vm.States = db.States.ToList();
vm.Citys = db.Citys.ToList();
vm.Zips = db.Zips.ToList();
return View(vm);
}
}
public ActionResult Edit(int? id)
{
if (id == null)
{
return NotFound();
}
var customervm = new CustomerFormVM();
{
Customer customer = db.Customers.SingleOrDefault(c => c.CustomerId == id);
if (customer == null)
{
return NotFound();
}
customervm.CustomerId = customer.CustomerId;
customervm.FirstName = customer.FirstName;
customervm.LastName = customer.LastName;
// Retrieve list of States
var states = db.States.ToList();
customervm.States = states;
// Retrieve list of Citys
var citys = db.Citys.ToList();
customervm.Citys = citys;
// Retrieve list of Citys
var zips = db.Zips.ToList();
customervm.Zips = zips;
// Set the selected state
customervm.StateId = customer.StateId;
// Set the selected city
customervm.CityId = customer.CityId;
// Set the selected zip
customervm.ZipId = customer.ZipId;
}
return View(customervm);
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(CustomerFormVM vmEdit)
{
if (ModelState.IsValid)
{
Customer customer = db.Customers.SingleOrDefault(c => c.CustomerId == vmEdit.CustomerId);
if (customer == null)
{
return NotFound();
}
customer.FirstName = vmEdit.FirstName;
customer.LastName = vmEdit.LastName;
customer.StateId = vmEdit.StateId;
customer.CityId = vmEdit.CityId;
customer.ZipId = vmEdit.ZipId;
db.Entry(customer).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(vmEdit);
}
}
创建视图
<div class="form-group">
@Html.LabelFor(c => c.FirstName)
@Html.TextBoxFor(c => c.FirstName, new { @class = "form-control" })
</div>
<div class="form-group">
@Html.LabelFor(c => c.LastName)
@Html.TextBoxFor(c => c.LastName, new { @class = "form-control" })
</div>
<div class="form-group">
@*@Html.LabelFor(s => s.StateId)
@Html.DropDownListFor(s => s.StateId, new SelectList(Model.States, "StateId", "Abbr"), "", new { @class = "form-control" })
@Html.ValidationMessageFor(s => s.StateId)*@
<label asp-for="StateId "></label>
<select asp-for="StateId " asp-items="Model.States" class="form-control" id="state-target"></select>
<span asp-validation-for="StateId " class="text-danger"></span>
</div>
<div class="form-group">
@*@Html.LabelFor(ct => ct.CityId)
@Html.DropDownListFor(ct => ct.CityId, new SelectList(Model.Citys, "CityId", "Name"), "", new { @class = "form-control" })
@Html.ValidationMessageFor(ct => ct.CityId)*@
<label asp-for="CityId"></label>
<select asp-for="CityId" asp-items="Model.Citys" class="form-control" id="city-target"></select>
<span asp-validation-for="CityId" class="text-danger"></span>
</div>
<div class="form-group">
@Html.LabelFor(z => z.ZipId)
@Html.DropDownListFor(z => z.ZipId, new SelectList(Model.Zips, "ZipId", "PostalCode"), "", new { @class = "form-control" })
@Html.ValidationMessageFor(z => z.ZipId)
</div>
<div class="form-group">
<button type="submit" class="btn btn-primary">Submit</button>
</div>
}
@section scripts {
<script src="~/lib/jquery-validation/dist/jquery.validate.js"></script>
<script src="~/lib/jquery-validation-unobtrusive/jquery.validate.unobtrusive.js"></script>
<script src="~/lib/js/example.js"></script>,
}
onchange="this.form.submit()"
。你需要在控制器中处理该提交并为下拉列表填充新的集合。 - Mackan