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由於兩個星期，我試圖創建一個包含3個下拉列表的ASP.NET MVC 4應用程序。 這些是國家，州和城市。 我繼this article使用Json和Jquery在Asp.net MVC4級聯下拉列表不填充
這些數據庫列表的詳細信息，我從databas叫
連接字符串：
<connectionStrings>
<add name="CACD_Con" connectionString="metadata=res://*/Models.Project_Name.csdl|res://*/Models.Project_Name.ssdl|res://*/Models.Project_Name.msl;provider=System.Data.SqlClient;provider connection string="data source=192.168.0.000;initial catalog=CACD;persist security info=True;user id=000;password=000000000;MultipleActiveResultSets=True;App=EntityFramework"" providerName="System.Data.EntityClient" />
</connectionStrings>
控制器類：
public class CacadingController : Controller
{
private ProjectContext db = new ProjectContext();
public ActionResult Index()
{
ViewBag.CountryId = new SelectList(db.Countrys, "CountryId", "CountryName");
return View();
}
public JsonResult StateList(int Id)
{
var state = from s in db.States
where s.CountryId == Id
select s;
return Json(new SelectList(state.ToArray(), "StateId", "StateName"), JsonRequestBehavior.AllowGet);
}
public JsonResult Citylist(int id)
{
var city = from c in db.Citys
where c.StateId == id
select c;
return Json(new SelectList(city.ToArray(), "CityId", "CityName"), JsonRequestBehavior.AllowGet);
}
public IList<State> Getstate(int CountryId)
{
return db.States.Where(m => m.CountryId == CountryId).ToList();
}
[AcceptVerbs(HttpVerbs.Get)]
public JsonResult LoadClassesByCountryId(string CountryName)
{
var stateList = this.Getstate(Convert.ToInt32(CountryName));
var stateData = stateList.Select(m => new SelectListItem()
{
Text = m.StateName,
Value = m.CountryId.ToString(),
});
return Json(stateData, JsonRequestBehavior.AllowGet);
}
}
模型類：
public partial class ProjectContext : DbContext
{
public ProjectContext()
: base("CACD")
{
}
public DbSet<Country> Countrys { get; set; }
public DbSet<State> States { get; set; }
public DbSet<City> Citys { get; set; }
}
public class Country
{
[Key]
public int CountryId { get; set; }
public string CountryName { get; set; }
public virtual ICollection<State> States { get; set; }
}
public class State
{
[Key]
public int StateId { get; set; }
public string StateName { get; set; }
[ForeignKey("Country")]
public int CountryId { get; set; }
public virtual Country Country { get; set; }
public virtual ICollection<City> Citys { get; set; }
}
public class City
{
[Key]
public int CityId { get; set; }
public string CityName { get; set; }
[ForeignKey("State")]
public int StateId { get; set; }
public virtual State State { get; set; }
}
查看文件（CSHTML）
@model Project_Name.Models.ProjectContext
@using (Html.BeginForm())
{
@Html.DropDownList("Country", ViewBag.CountryId as SelectList, "Select a Country", new { id="Country" })<br />
<select id="State" name="state"></select><br />
<select id="city" name="City"></select><br />
}
@Scripts.Render("~/bundles/jquery")
<script type="text/jscript">
$(function() {
$('#Country').change(function() {
$.getJSON('/Cascading/StateList/' + $('#Country').val(), function (data) {
var items = '<option>Select a State</option>';
$.each(data, function (i, state) {
items += "<option value='" + state.Value + "'>" + state.Text + "</option>";
});
$('#State').html(items);
});
});
$('#State').change(function() {
$.getJSON('/Cascading/Citylist/' + $('#State').val(), function (data) {
var items = '<option>Select a City</option>';
$.each(data, function (i, city) {
items += "<option value='" + city.Value + "'>" + city.Text + "</option>";
});
$('#city').html(items);
});
});
});
</script>
但是下拉不能顯示任何在數據庫中的數據，很感激，如果你能告訴我正確的路徑
請告訴我不工作？第一個下拉列表（國家）正在填充？ –
沒有任何上述dropdwon不填充任何東西 – kez
然後，你需要調試你的代碼 - 是否'db.Countrys'返回任何有效的數據？ （並且你不需要'@model AFFEMS2_HEC.Models.ProjectContext'在視圖中 - 這不是你的模型！） –