MVC SelectList在文本字段中组合多列 [英] MVC SelectList combining multiple columns in text field

问题描述

我将如何生成一个选择列表，其中文本字段由两个或多个文本列组成，例如:如果我的数据库中有一个描述和速率字段，我想将它们组合起来显示:

大--£200中等--£150小——100英镑

控制器代码为:

 var stand = db.Stands.Where(s => s.ExhibitorID == null).ToList();ViewBag.StandID = new SelectList(stands,"StandID", "Description" + "-- £" + "Rate");

...我的观点是(目前):

 
@Html.DropDownList("StandID", "--Select--")

...但是描述"+--£"+价格")；不会运行:

<块引用>

数据绑定:'System.Data.Entity.DynamicProxies.Stand_63F8C9F623B3C0E57D3008A57081AFCD9C39E1A6B79B0380B60840F1EFAE9DB4'不包含名为Description--£Rate"的属性.

感谢您的帮助，

标记

解决方案

您可以使用简单的 LINQ 投影创建一个新的匿名类，然后使用 SelectList(IEnumerable, string, string) 构造函数重载 用于指定值和文本字段用于 元素，即:

var 代表 =db.stands.Where(s => s.ExhibitorID == null).Select(s => new{StandID = s.StandID,Description = string.Format("{0}-- £{1}", s.Description, s.Rate)}).ToList();ViewBag.StandID = new SelectList(stands, "StandID", "Description")

编辑

在 C#6 及更高版本中，字符串插值使得效果更好阅读比string.Format

<代码> ...描述 = $"{s.Description}-- £{s.Rate}"

如果你投射到一个强 ViewModel 类名(而不是一个匿名类)，你无疑会想用 nameof 运营商:

ViewBag.StandID = new SelectList(stands, nameof(Stand.StandID), nameof(Stand.Description));

How would I generate a select list, where the text field, is made up of two or more text columns, eg: Where I have a Description and Rate field in my database, I want to combine these to show:

Large--£200
Medium--£150
Small--£100

Controller code is:

 var stands = db.Stands.Where(s => s.ExhibitorID == null).ToList();
 ViewBag.StandID = new SelectList(stands,"StandID", "Description" + "-- £" + "Rate");

...and my view is (currently):

    <div class="editor-field"> 
        @Html.DropDownList("StandID", "--Select--") 
    </div> 

...but the "Description" + "-- £" + "Rate"); won't run:

DataBinding: 'System.Data.Entity.DynamicProxies.Stand_63F8C9F623B3C0E57D3008A57081AFCD9C39E1A6B79B0380B60840F1EFAE9DB4' does not contain a property with the name 'Description--£Rate'.

Thanks for any help,

Mark

解决方案

You could create a new anonymous class using a simple LINQ projection, and then use the SelectList(IEnumerable, string, string) constructor overload to specify the value and text fields to be used for the <option> elements i.e.:

var stands = 
  db.Stands
    .Where(s => s.ExhibitorID == null)
    .Select(s => new 
     { 
       StandID = s.StandID,
       Description = string.Format("{0}-- £{1}", s.Description, s.Rate) 
     })
    .ToList();

ViewBag.StandID = new SelectList(stands, "StandID", "Description")

Edit

In C#6 and later, string interpolation makes for better reading than string.Format

   ...
   Description = $"{s.Description}-- £{s.Rate}"

If you project to a strong ViewModel class name (instead of to an anonymous class), you will undoubtedly want to replace the magic strings with the safety of the nameof operator:

ViewBag.StandID = new SelectList(stands, nameof(Stand.StandID), nameof(Stand.Description));

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