asp.net-mvc ASP.NET MVC - 级联下拉菜单

ASP.NET MVC - Cascading Drop Down

提问by Ros

I'm currently learning ASP.NET MVC and using Nhibernate.

我目前正在学习 ASP.NET MVC 并使用 Nhibernate。

I would like to use Cascading Drop-Down Boxes. Has anyone managed to get cascading drop-down boxes working in MVC?

我想使用级联下拉框。有没有人设法让级联下拉框在 MVC 中工作？

Updated: I have looked at the following website: link textand used method 1.

更新：我查看了以下网站：链接文本和使用的方法 1。

Controller Code

控制器代码

        var makeList = new SelectList(makeRepository.ListMakes (), "Id", "make",1);
        ViewData["Makes"] = makeList;

        //// Create Models view data
        var modelList = new CascadingSelectList(modelRepository.ListModels (Convert.ToInt32(makeList.SelectedValue.ToString())), "ModelID","Id", "Name");
        ViewData["Models"] = modelList;

View Code

查看代码

<%= Html.DropDownList("--Select Make--","Makes")%>
<label for="Makes">Car Model:</label>    
<%= Html.CascadingDropDownList("Models", "Makes") %> 

The correct list of cars is listed when a Make with id of 1 is selected, but when I select a different make the model list is empty?

选择 id 为 1 的制造时会列出正确的汽车列表，但是当我选择不同的制造时，模型列表为空？

回答by alex

You may want to read this TIP.

您可能想阅读此提示。

In this tip, Stephen Walter demonstrates three methods of creating cascading dropdown lists. First, he shows you how to alter the list of options displayed by one dropdown list when an option in another dropdown list changes. Second, he shows you how to expose the data for the dropdown lists through a controller action. Next, he shows you how to grab the data for the dropdown lists from web services.

在本技巧中，Stephen Walter 演示了创建级联下拉列表的三种方法。首先，他向您展示了如何在另一个下拉列表中的选项发生更改时更改一个下拉列表中显示的选项列表。其次，他向您展示了如何通过控制器操作公开下拉列表的数据。接下来，他将向您展示如何从 Web 服务获取下拉列表的数据。

回答by Pieter Germishuys

You might want to have a look at a postI made a couple of weeks ago on exactly this

你可能想看看我几周前发表的一篇关于这个的帖子

First we will need to setup the JsonResult controller action.

首先，我们需要设置 JsonResult 控制器操作。

/// <summary></summary>  
/// Get Models
/// <param name="makeID" />  
/// <returns></returns>  
public JsonResult GetModels(string id)  
{       
   JsonResult result = new JsonResult();       
   var filteredModels = from model in homeViewModel.Models
                        where model.MakeID.ToString() == id
                        select model;       result.Data = filteredModels.ToList();
   result.JsonRequestBehavior = JsonRequestBehavior.AllowGet;    
   return result;  
} 

This method now gives us the ability to use the nifty $.getJSONjquery call. The signature for the call is as follows

这个方法现在让我们能够使用漂亮的$.getJSONjquery 调用。调用的签名如下

jQuery.getJSON( url, [ data ], [ callback(data, textStatus) ] )

Given that we have setup 2 Drop Down Lists, one for Makes and the other for Models, like so.

鉴于我们已经设置了 2 个下拉列表，一个用于品牌，另一个用于模型，就像这样。

   Html.DropDownListFor((model) => model.MakeID, new SelectList(Model.Makes, "ID", "Description"))    
   Html.DropDownListFor((model) => model.ModelID, new SelectList(Model.Models, "ID", "Description"))

we can include the following bit of jquery

我们可以包含以下 jquery

//Hook onto the MakeID list's onchange event  
$("#MakeID").change(function() {   
   //build the request url   
   var url = '<!--Url.Content("~/")-->' + 'Home/GetModels';

   //fire off the request, passing it the id which is the MakeID's selected item value   
   $.getJSON(url, { id: $("#MakeID").val() }, function(data) {    
      //Clear the Model list    
      $("#ModelID").empty();    
      //Foreach Model in the list, add a model option from the data returned    
      $.each(data, function(index, optionData) {       
         $("ModelID").append("<option value=" + optionData.ID +">"+ optionData.Description +"</option>"  );    
      });
   });  
}).change();

Sorry for the shameless plug :(

对不起无耻的插件:(

回答by Raj Kaimal

I have created a jQuery plugin for this.

我为此创建了一个 jQuery 插件。

http://weblogs.asp.net/rajbk/archive/2010/05/20/cascadingdropdown-jquery-plugin-for-asp-net-mvc.aspx

http://weblogs.asp.net/rajbk/archive/2010/05/20/cascadingdropdown-jquery-plugin-for-asp-net-mvc.aspx

回答by Raj Kaimal

The Tip you are using: ASP.NET MVC Tip #41 – Create Cascading Dropdown Lists with Ajax from Stephen Walther was not done with MVC Realease 1.0

您正在使用的提示：ASP.NET MVC 提示 #41 – Create Cascading Dropdown Lists with Ajax from Stephen Walther 不是使用 MVC Realease 1.0 完成的

As such, it works fine with the downloaded project (after fixing some small issues), but when the you try to incorporate into MVC Release 1.0 things break.

因此，它在下载的项目中运行良好（在修复了一些小问题之后），但是当您尝试将其合并到 MVC 版本 1.0 时，事情就会中断。

For example: in the downloaded project, the scripts are in the Content Folder, in Release 1.0, the scripts are in the Scripts folder.

例如：在下载的项目中，脚本位于 Content 文件夹中，在 Release 1.0 中，脚本位于 Scripts 文件夹中。

Also some (if not all) of the *.js files in the release changed from the bets and CTPs. This may be a problem too.

发行版中的一些（如果不是全部）*.js 文件也从赌注和 CTP 改变了。这也可能是个问题。

I downloaded his project (fixed a couple of minor issues), and it worked fine within that project (the *.js files).

我下载了他的项目（修复了几个小问题），并且在该项目（*.js 文件）中运行良好。

For Example,

例如，

I Fixed the following as:

我修复了以下内容：

CHANGE: \Views\Home\index.aspx

改变： \Views\Home\index.aspx

<label for="Makes">Car Make:</label>  
<%= Html.DropDownList("--Select Make--", "Makes") %>

TO:

到：

<label for="Makes">Car Make:</label>
<%= Html.DropDownList("Makes", (SelectList)ViewData["Makes"], "--Select Make--")%>

So as you see, there are some issues.

所以如你所见，有一些问题。

These type problems with tutorials and blogs are abundant; everyone wants to be considered an "Expert" on new technology being released so they write tutorials on betas and CTPs. The result is that the "Expert" will have stuff that doesn't work with the final release.

这些教程和博客的类型问题很丰富；每个人都希望被视为发布新技术的“专家”，因此他们编写有关测试版和 CTP 的教程。结果是“专家”将有一些不适用于最终版本的东西。

What you need to find is a Professional that has posted tutorials. A Professional will ensure that their tutorials work. What I mean by a professional is a professional trainer in that area of technology.

您需要找到发布教程的专业人士。专业人士将确保他们的教程有效。我所说的专业人士是指该技术领域的专业培训师。

Stephen Walther has one of the better blogs and a lot of good stuff, but remember that he is a Microsoift Evangelist. He authors books on MS technology so he needs to be active in the blog world so he puts some good stuff out on leading edge technology. This keeps him deemed as an expert so his books can sell.

Stephen Walther 有一个更好的博客和很多好东西，但请记住，他是一名 Microsoift 布道者。他撰写了有关 MS 技术的书籍，因此他需要活跃在博客世界中，因此他会在前沿技术方面发表一些好文章。这使他被视为专家，因此他的书可以出售。

Just remember, regardless of the "Expert", there will be inaccuracies in blogs/writings (based on betas and CTPs) when you try to use the information in a final release.

请记住，无论“专家”如何，当您尝试在最终版本中使用这些信息时，博客/文章（基于测试版和 CTP）都会存在不准确之处。