C# MVC Razor两级级联列表框赢得'；t滤波器

我试图实现

但当我跑步时，我不会成功。我总是出错。我希望有人能查看我的代码。我想不出错误在哪里

型号

//LineMaintenance.cs
namespace SchneiderDMS.Models
{
using System;
using System.Collections.Generic;

public partial class LineMaintenance
{
    public int ID { get; set; }
    public Nullable<int> LineID { get; set; }
    public Nullable<System.DateTime> StartTime { get; set; }
    public Nullable<System.DateTime> AcknowlegeTime { get; set; }
    public Nullable<System.DateTime> EndTime { get; set; }
    public Nullable<int> TypeOfProblemID { get; set; }
    public Nullable<int> ProblemID { get; set; }
    public string ProblemDescription { get; set; }
    public virtual Line Line { get; set; }
    public virtual Problem Problem { get; set; }
    public virtual TypeOfProblem TypeOfProblem { get; set; }
}
}


//Problem.cs
namespace SchneiderDMS.Models
{
using System;
using System.Collections.Generic;

public partial class Problem
{
    public Problem()
    {
        this.LineMaintenances = new HashSet<LineMaintenance>();
    }

    public int ID { get; set; }
    public Nullable<int> TypeOfProblemID { get; set; }
    public string Name { get; set; }
    public virtual ICollection<LineMaintenance> LineMaintenances { get; set; }
    public virtual TypeOfProblem TypeOfProblem { get; set; }
}
}


//TypeOfProblem.cs
namespace SchneiderDMS.Models
{
using System;
using System.Collections.Generic;

public partial class TypeOfProblem
{
    public TypeOfProblem()
    {
        this.LineMaintenances = new HashSet<LineMaintenance>();
        this.Problems = new HashSet<Problem>();
    }

    public int ID { get; set; }
    public string Name { get; set; }
    public virtual ICollection<LineMaintenance> LineMaintenances { get; set; }
    public virtual ICollection<Problem> Problems { get; set; }
}
}

<div class="col-md-4">
   @Html.LabelFor(model => model.TypeOfProblemID, "TypeOfProblemID", htmlAttributes: new { @class = "control-label", @style = "margin-bottom:10px" })
   @Html.ListBox("TypeOfProblemID", null, htmlAttributes: new { @class = "form-control", @style = "height:150px" })
   @Html.ValidationMessageFor(model => model.TypeOfProblemID, "", new { @class = "text-danger" })
</div>
<div class="col-md-4">
   @Html.LabelFor(model => model.ProblemID, "ProblemID", htmlAttributes: new { @class = "control-label", @style = "margin-bottom:10px" })
   @Html.ListBox("ProblemID", null , htmlAttributes: new { @class = "form-control", @style = "height:150px" })
   @Html.ValidationMessageFor(model => model.ProblemID, "", new { @class = "text-danger" })
</div>

@section Scripts {
@Scripts.Render("~/bundles/jqueryvalc")
<script> 
$(document).ready(function () 
{ 
    //Dropdownlist Selectedchange event 
    $("#TypeOfProblemID").change(function () 
    { 
        $("#ProblemID").empty(); 
        $.ajax({ 
            type:'POST', 
            url: '@Url.Action("SelectProblems")', 
            dataType: 'json', 
            data: { id: $("#TypeOfProblemID").val() }, 
            success: function (Problems) 
            { 
                // Problems contains the JSON formatted list 
                // of Problems passed from the controller 
                $.each(Problems, function (i, Problem) 
                { 
                    $("#ProblemID").append('<option value="' 
                     + Problem.ID + '">' 
                     + Problem.Name + '</option>'); 
                }); 
            }, 
            error: function (ex) 
            { 
                alert('Failed to retrieve Problems.' + ex); 
            } 
        }); 
        return false; 
    }) 
}); 
</script>
}

//LineMaintenance.cs
名称空间SchneiderDMS.Models
{
使用制度；
使用System.Collections.Generic；
公共部分类线路维护
{
公共int ID{get；set；}
公共可为空的LineID{get；set；}
公共可为空的开始时间{get；set；}
公共可空的AcknowleGetTime{get；set；}
公共可为null的结束时间{get；set；}
问题ID{get；set；}的公共可空类型
公共可为空的问题ID{get；set；}
公共字符串ProblemDescription{get；set；}
公共虚拟行{get；set；}
公共虚拟问题{get；set；}
公共虚拟类型问题类型问题{get；set；}
}
}
//Problem.cs
名称空间SchneiderDMS.Models
{
使用制度；
使用System.Collections.Generic；
公共部分类问题
{
公共问题（）
{
this.LineMaintenances=new HashSet（）；
}
公共int ID{get；set；}
问题ID{get；set；}的公共可空类型
公共字符串名称{get；set；}
公共虚拟ICollection行维护{get；set；}
公共虚拟类型问题类型问题{get；set；}
}
}
//问题的类型
名称空间SchneiderDMS.Models
{
使用制度；
使用System.Collections.Generic；
问题的公共部分类类型
{
问题（）的公共类型
{
this.LineMaintenances=new HashSet（）；
this.Problems=newhashset（）；
}
公共int ID{get；set；}
公共字符串名称{get；set；}
公共虚拟ICollection行维护{get；set；}
公共虚拟ICollection问题{get；set；}
}
}

查看-创建.cshtml

//LineMaintenance.cs
namespace SchneiderDMS.Models
{
using System;
using System.Collections.Generic;

public partial class LineMaintenance
{
    public int ID { get; set; }
    public Nullable<int> LineID { get; set; }
    public Nullable<System.DateTime> StartTime { get; set; }
    public Nullable<System.DateTime> AcknowlegeTime { get; set; }
    public Nullable<System.DateTime> EndTime { get; set; }
    public Nullable<int> TypeOfProblemID { get; set; }
    public Nullable<int> ProblemID { get; set; }
    public string ProblemDescription { get; set; }
    public virtual Line Line { get; set; }
    public virtual Problem Problem { get; set; }
    public virtual TypeOfProblem TypeOfProblem { get; set; }
}
}


//Problem.cs
namespace SchneiderDMS.Models
{
using System;
using System.Collections.Generic;

public partial class Problem
{
    public Problem()
    {
        this.LineMaintenances = new HashSet<LineMaintenance>();
    }

    public int ID { get; set; }
    public Nullable<int> TypeOfProblemID { get; set; }
    public string Name { get; set; }
    public virtual ICollection<LineMaintenance> LineMaintenances { get; set; }
    public virtual TypeOfProblem TypeOfProblem { get; set; }
}
}


//TypeOfProblem.cs
namespace SchneiderDMS.Models
{
using System;
using System.Collections.Generic;

public partial class TypeOfProblem
{
    public TypeOfProblem()
    {
        this.LineMaintenances = new HashSet<LineMaintenance>();
        this.Problems = new HashSet<Problem>();
    }

    public int ID { get; set; }
    public string Name { get; set; }
    public virtual ICollection<LineMaintenance> LineMaintenances { get; set; }
    public virtual ICollection<Problem> Problems { get; set; }
}
}

<div class="col-md-4">
   @Html.LabelFor(model => model.TypeOfProblemID, "TypeOfProblemID", htmlAttributes: new { @class = "control-label", @style = "margin-bottom:10px" })
   @Html.ListBox("TypeOfProblemID", null, htmlAttributes: new { @class = "form-control", @style = "height:150px" })
   @Html.ValidationMessageFor(model => model.TypeOfProblemID, "", new { @class = "text-danger" })
</div>
<div class="col-md-4">
   @Html.LabelFor(model => model.ProblemID, "ProblemID", htmlAttributes: new { @class = "control-label", @style = "margin-bottom:10px" })
   @Html.ListBox("ProblemID", null , htmlAttributes: new { @class = "form-control", @style = "height:150px" })
   @Html.ValidationMessageFor(model => model.ProblemID, "", new { @class = "text-danger" })
</div>

@section Scripts {
@Scripts.Render("~/bundles/jqueryvalc")
<script> 
$(document).ready(function () 
{ 
    //Dropdownlist Selectedchange event 
    $("#TypeOfProblemID").change(function () 
    { 
        $("#ProblemID").empty(); 
        $.ajax({ 
            type:'POST', 
            url: '@Url.Action("SelectProblems")', 
            dataType: 'json', 
            data: { id: $("#TypeOfProblemID").val() }, 
            success: function (Problems) 
            { 
                // Problems contains the JSON formatted list 
                // of Problems passed from the controller 
                $.each(Problems, function (i, Problem) 
                { 
                    $("#ProblemID").append('<option value="' 
                     + Problem.ID + '">' 
                     + Problem.Name + '</option>'); 
                }); 
            }, 
            error: function (ex) 
            { 
                alert('Failed to retrieve Problems.' + ex); 
            } 
        }); 
        return false; 
    }) 
}); 
</script>
}

@LabelFor（model=>model.TypeOfProblemID，“TypeOfProblemID”，htmlAttributes:new{@class=“control label”，@style=“margin bottom:10px”}）
@ListBox（“TypeOfProblemID”，null，htmlAttributes:new{@class=“form control”，@style=“height:150px”}）
@Html.ValidationMessageFor（model=>model.TypeOfProblemID，“，new{@class=“text danger”}）
@LabelFor（model=>model.ProblemID，“ProblemID”，htmlAttributes:new{@class=“control label”，@style=“margin bottom:10px”}）
@ListBox（“ProblemID”，null，htmlAttributes:new{@class=“form control”，@style=“height:150px”}）
@Html.ValidationMessageFor（model=>model.ProblemID，“，new{@class=“text danger”}）
@节脚本{
@Scripts.Render（“~/bundles/jqueryvalc”）
$（文档）.ready（函数（）
{ 
//下拉列表Selectedchange事件
$（“#TypeOfProblemID”）.change（函数（）
{ 
$（“#ProblemID”）.empty（）；
$.ajax（{
类型：'POST'，
url:“@url.Action”（“SelectProblems”），
数据类型：“json”，
数据：{id:$（“#TypeOfProblemID”）.val（），
成功：功能（问题）
{ 
//问题包含JSON格式的列表
//从控制器传递的问题的数量
$。每个（问题，功能（i，问题）
{ 
$（“#ProblemID”）.append（“”
+问题。名称+“”）；
}); 
}, 
错误：函数（ex）
{ 
警报（“检索问题失败”。+ex）；
} 
}); 
返回false；
}) 
}); 
}

控制器-线路维护.cs

    // GET: LineMaintenances/Create
    public ActionResult Create()
    {
        ViewBag.LineID = new SelectList(db.Lines, "ID", "Name");
        ViewBag.ProblemID = new SelectList(db.Problems, "ID", "Name");
        ViewBag.TypeOfProblemID = new SelectList(db.TypeOfProblems, "ID", "Name");
        return View();
    }

    //Returns Json Result
    public JsonResult SelectProblems(int id)
    {
        db.Configuration.ProxyCreationEnabled = false;
        IEnumerable<Problem> Problems = db.Problems.Where(p => p.TypeOfProblemID == id);
        return Json(Problems);
    }

    // POST: LineMaintenances/Create
    // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
    // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Create([Bind(Include = "ID,LineID,StartTime,AcknowlegeTime,EndTime,TypeOfProblemID,ProblemID,ProblemDescription")] LineMaintenance lineMaintenance)
    {
        if (ModelState.IsValid)
        {
            db.LineMaintenances.Add(lineMaintenance);
            await db.SaveChangesAsync();
            return RedirectToAction("Index");
        }

        ViewBag.LineID = new SelectList(db.Lines, "ID", "Name", lineMaintenance.LineID);
       // ViewBag.ProblemID = new SelectList(db.Problems, "ID", "Name", lineMaintenance.ProblemID);
        ViewBag.TypeOfProblemID = new SelectList(db.TypeOfProblems, "ID", "Name", lineMaintenance.TypeOfProblemID);
        return View(lineMaintenance);
    }

//GET:LineMaintenances/Create
公共操作结果创建（）
{
ViewBag.LineID=新选择列表（db.Lines，“ID”，“Name”）；
ViewBag.ProblemID=新选择列表（db.Problems，“ID”，“Name”）；
ViewBag.TypeOfProblemID=新选择列表（db.TypeOfProblems，“ID”，“Name”）；
返回视图（）；
}
//返回Json结果
公共JsonResult SelectProblems（int id）
{
db.Configuration.ProxyCreationEnabled=false；
IEnumerable Problems=db.Problems.Where（p=>p.TypeOfProblemID==id）；
返回Json（问题）；
}
//发布：线路维护/创建
//若要防止套印攻击，请启用要绑定到的特定属性，例如
//更多详细信息请参见http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
公共异步任务创建（[Bind（Include=“ID，LineID，StartTime，AcknowlegeTime，EndTime，TypeOfProblemID，ProblemID，ProblemDescription”）]LineMaintenance-LineMaintenance
{
if（ModelState.IsValid）
{
db.LineMaintenances.Add（LineMaintenances）；
等待db.saveChangesSync（）；
返回操作（“索引”）；
}
ViewBag.LineID=新建选择列表（db.Lines，“ID”，“Name”，lineMaintenance.LineID）；
//ViewBag.ProblemID=新建选择列表（db.Problems，“ID”，“Name”，lineMaintenance.ProblemID）；
ViewBag.TypeOfProblemID=新选择列表（db.TypeOfProblems，“ID”，“Name”，lineMaintenance.TypeOfProblemID）；
返回视图（线路维护）；
}

在您返回json结果时，在您的代码中修改它，如下所示

public JsonResult SelectProblems(int id)
{
    db.Configuration.ProxyCreationEnabled = false;
    IEnumerable<Problem> Problems = db.Problems.Where(p => p.TypeOfProblemID == id);
    return Json(Problems,JsonRequestBehavior.AllowGet);
}

public JsonResult SelectProblems（int-id）
{
db.Configuration.ProxyCreationEnabled=false；
IEnumerable Problems=db.Problems.Where（p=>p.TypeOfProblemID==id）；
返回Json（Problems，JsonRequestBehavior.AllowGet）；
}