在system.web.mvc.dll中但未在用户代码中处理其他信息：没有类型为'ienumerable< selectlistitem>'的viewdata项目具有关键'状态'的。 [英] In system.web.mvc.dll but was not handled in user code additional information: there is no viewdata item of type 'ienumerable<selectlistitem>' that has the key 'state'.

问题描述

Quote：

System.Web.Mvc.dll中出现'System.InvalidOperationException'类型的异常，但未在用户代码中处理附加信息：没有类型为'IEnumerable< selectlistitem>'的ViewData项目，其键有'State'。

这里是我的控制器： -

使用ebpassprojects.Models; 
使用System; 
使用System.Collections.Generic; 
使用System.Linq; 
使用System.Web; 
使用System.Web.Mvc; 
使用ebpassprojects; 
使用System.Data.Entity; 
 
 
名称空间ebpassprojects.Controllers 
 {
公共类ListController：Controller 
 {
 // GET：List 
 
 private ApplicationDbContext db = new ApplicationDbContext（）; 
 private void PopulateLookups（ApplicationDbContext db）
 {
 IEnumerable< SelectListItem> item = db.allofcity.Select（C => new SelectListItem 
 {
 Value = C.cities，
 Text = C.cities 
}）。ToList（）; 
 
 ViewBag.city = item; 
 
 IEnumerable< SelectListItem> item = db.allofstate.Select（C => new SelectListItem 
 {
 Value = C.States，
 Text = C.States 
}）。ToList（）; 
 
 ViewBag.state = item; 
} 
 
 
} 
} 

和我的观点： -

< div class =form-group> 
 @ Html.LabelFor（m => m.State，new {@class =col-md-2 control-label}）
< div class =col-md-10 > 
 @ Html.DropDownListFor（m => m.State，（IEnumerable< SelectListItem>）ViewBag.state，Select College，new {@class =form-control}）
< / DIV> 
< / div> 
< div class =form-group> 
 @ Html.LabelFor（m => m.City，new {@class =col-md-2 control-label}）
< div class =col-md-10 > 
 @Html.DropDownListFor（m => m.City，（IEnumerable< SelectListItem>）ViewBag.city，Select College，new {@class =form-control}）
< / DIV> 
< / div> 
 

我的尝试：



i尝试过viewdata而不是viewbag，但它仍然没有显示

解决方案

你的代码似乎没问题，很有可能像@Graeme_Grant所指出的那样，代码从模型中缺少State属性/属性。这是一个快速测试/示例。我假设PopulateLookups方法正在运行，我认为它是。



1.创建一个非常简单的类，我们称之为TestState

  public   class  TestState 
 {
 < span class =code-keyword> public   string 状态{ get ;  set ; } 
} 

2.选择一个控制器/动作，在我的情况下，我选择回家/索引

  public  ActionResult Index（）
 {
 PopulateLookups（db）; 
 
  return 查看（）; 
} 

3.在索引视图中，添加顶部的模型及其下方的下拉菜单

 @ model WebApplication4.Models.TestState 
 
< div  class  =   form-group >  
 @ Html.LabelFor（m = >  m.State， new  {@class =   col-md-2 control-label}）
< div  class  =   col-md-10 >  
 @ Html.DropDownListFor（m = >  m.State，（IEnumerable< SelectListItem>）ViewBag.state， new  {@class =  表单-control}）
 < /   div  >  
 < /   div  >  

4.运行应用程序，导航到home / index，您应该看到包含State的下拉列表。



5.如果＃4工作证明您当前的模型缺少属性，请在模型中添加一个在视图中引用的State属性。如果仍然不起作用，发布更多代码，再次与我们共享模型/视图//控制器/

 IEnumerable< SelectListItem> itenn = ... 
 ViewBag.state = itenn; 

拼写错误.. itenn 应为 item



此外，您已将该属性从州更改为价值与优惠文本（？）here：

 Enumerable< SelectListItem> itenn = db.allofstate.Select（C = >   new  SelectListItem 
 {
 Value = C.States，
 Text = C.States 
}）。ToList（）; 

发布此工作示例，来自之前的Q& A支持会议。原则仍然相同：



1.数据模型：

  public   class  DataModel 
 {
  public  Queue< List< string>>数据{获取;  set ; } 
 =  new 队列< List< string>>（）; 
} 

2。控制器

  public   class  HomeController：Controller 
 {
  public  ActionResult Index（）
 {
  var  results =  new  DataModel（）; 
  for （ int  i =  0 ; i <   10 ; i ++）
 {
 results.Data .Enqueue（ new  List< string>（）{  aaa，  bbb，   ccc}）; 
} 
  return 查看（results.Data）; 
} 
} 

2。查看

 @ {
 ViewBag.Title =队列数据测试; 
} 
 @Model = IEnumerable <   List< string  > 取代; 
 <   div  >  
 @foreach（模型中的var项）
 {
 <   p  > 数据：
 @ string.Join（，，item）; 
 <   / p  >  
} 
 <   / div  >  

Quote:

An exception of type 'System.InvalidOperationException' occurred in System.Web.Mvc.dll but was not handled in user code Additional information: There is no ViewData item of type 'IEnumerable<selectlistitem>' that has the key 'State'.

here is my controller :-

using ebpassprojects.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using ebpassprojects;
using System.Data.Entity;


namespace ebpassprojects.Controllers
{
    public class ListController : Controller
    {
        // GET: List

        private ApplicationDbContext db = new ApplicationDbContext();
        private void PopulateLookups(ApplicationDbContext db)
        {
            IEnumerable<SelectListItem> item = db.allofcity.Select(C => new SelectListItem
            {
                Value = C.cities,
                Text = C.cities
            }).ToList();

            ViewBag.city= item;

            IEnumerable<SelectListItem> item = db.allofstate.Select(C => new SelectListItem
            {
                Value = C.States,
                Text = C.States
            }).ToList();

            ViewBag.state = item;
        }


    }
}

and my view :-

<div class="form-group">
               @Html.LabelFor(m => m.State, new { @class = "col-md-2 control-label" })
               <div class="col-md-10">
                   @Html.DropDownListFor(m => m.State, (IEnumerable<SelectListItem>)ViewBag.state, "Select College", new { @class = "form-control" })
               </div>
           </div>
           <div class="form-group">
               @Html.LabelFor(m => m.City, new { @class = "col-md-2 control-label" })
               <div class="col-md-10">
                   @Html.DropDownListFor(m => m.City, (IEnumerable<SelectListItem>)ViewBag.city, "Select College", new { @class = "form-control" })
               </div>
           </div>

What I have tried:

i have tried viewdata instead of viewbag but its still not showing

解决方案

Your code seem ok, very likely, like @Graeme_Grant had pointed out, the code is missing "State" attribute/property from the Model. Here a quick test/example. I'm assuming PopulateLookups method is functioning, which I think it is.

1. Create a very simple class, let call it TestState

public class TestState
    {
        public string State { get; set; }
    }

2. Pick a controller/action, in my case, I picked home/Index

public ActionResult Index()
        {
            PopulateLookups(db);
  
            return View();
        }

3. In the Index View, add the Model on the top and the dropdown below it

@model WebApplication4.Models.TestState

<div class="form-group">
        @Html.LabelFor(m => m.State, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.DropDownListFor(m => m.State, (IEnumerable<SelectListItem>)ViewBag.state, new { @class = "form-control" })
        </div>
    </div>

4. Run the application, navigate to home/index, you should see the dropdownlist with State in it.

5. If #4 work that proof your current Model is missing a property, add a State property in your Model that being referenced in the view. If that still doesn't work, post more code, share the model/view//controller with us again/

IEnumerable<SelectListItem> itenn = ...
ViewBag.state = itenn;

Spelling error.. itenn should beitem

Also, you have changed the property from State to Value & Text (?) here:

Enumerable<SelectListItem> itenn = db.allofstate.Select(C => new SelectListItem
            {
                Value = C.States,
                Text = C.States
            }).ToList();

Posting this working example, from a previous Q&A support session. Principle is still the same:

1. Data Model:

public class DataModel
{
    public Queue<List<string>> Data { get; set; } 
        = new Queue<List<string>>();
}

2. Controller

public class HomeController : Controller
{
    public ActionResult Index()
    {
        var results = new DataModel();
        for (int i = 0; i < 10; i++)
        {
            results.Data.Enqueue(new List<string>() { "aaa", "bbb", "ccc" });
        }
        return View(results.Data);
    }
}

2. View

@{
    ViewBag.Title = "Queue Data Test";
}
@Model = IEnumerable<List<string>>;
<div>
    @foreach (var item in Model)
    {
        <p> data: 
        @string.Join(", ", item);
        </p>
    }
</div>

这篇关于在system.web.mvc.dll中但未在用户代码中处理其他信息：没有类型为'ienumerable&lt; selectlistitem&gt;'的viewdata项目具有关键'状态'的。的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！