在MVC3创建下拉列表 [英] Creating Dropdown List in MVC3
问题描述
我想创建一个下拉列表中显示的自定义集合类的所有值
如
公共类MyCustomClassCollection
{公开名单＆LT; MyCustomClass＆GT; {获取;设置;}}
我想让它显示了说明：每个MyCustomClass字符串
我试过
＆LT;％：＆GT Html.DropDownList说明，MyCustomClass％;
ReSharper的建议我投MyCustomClass到IEnemerable
但服务器返回一个无法施放的错误。
任何想法我怎么能创造这个DropDownList的？
的__ 修改的 _ __
公共类视图模型
{
公众详细细节{搞定;组; }
}公共类细节//从webservce继承
{
公共CustomClassCollection {获取;设置;}
....其他属性，a.k.a自定义类别
}
公共类CustomClassCollection
{
公开名单＆LT; CustomClass＆GT; {获取;设置;}
}公共类CustomClass {
公众诠释标识{获取;设置;}
公共字符串描述{获取;设置;}
...其他属性}
公众的ActionResult指数（INT？编号，日期时间？日）
{
如果（id.Equals（空））
ID = #########;
如果（date.Equals（空））
日期= DateTime.Today;
VAR VM =新的ViewModel
{
详细= _repository.Detail（（INT）ID，（日期时间）为准）
};
返回查看（VM）;
}
的的DropDownList 助手的第二个参数必须是一个的IEnumerable＆LT; SelectListItem＆GT; 或的SelectList 实现此接口为此事。因此，在你的控制器动作组织在您将您的自定义收集到这样的IEnumerable＆LT; SelectListItem＆GT; 。与往常一样，你可以通过编写一个视图模型启动：
公共类MyViewModel
{
公共字符串SelectedDescription {搞定;组; }
公众的SelectList说明{搞定;组; }
}
，然后让你的控制器操作查询自定义列表，并填充会传递给视图视图模型：
公众的ActionResult指数（）
{
VAR描述= yourCustomCollection.MyCustomClass.Select（X =＆gt;新建
{
值= x.Description，
文字= x.Description
}）;
VAR模型=新MyViewModel
{
说明=新的SelectList（描述中，价值，文本）
};
返回查看（模型）;
}
终于在你的强类型的视图：
＆LT;％= Html.DropDownListFor（X =＆GT; x.SelectedDescription，Model.Decriptions）％GT;
更新：
发布更新的模型（其中的方式仍然是不完整的，也不可能编译因为你没有提供任何属性名称）后，这里是一个例子：
公共类视图模型
{
公众诠释SelectedId {搞定;组; }
公众详细细节{搞定;组; }
}公共类细节
{
公共CustomClassCollection MyCollection的{搞定;组; }
}
公共类CustomClassCollection
{
公开名单＆LT; CustomClass＆GT; CustomClass {搞定;组; }
}公共类CustomClass
{
公众诠释标识{搞定;组; }
公共字符串描述{搞定;组; }
}公共类HomeController的：控制器
{
公众的ActionResult指数（）
{
VAR VM =新的ViewModel
{
细节=新的细节
{
MyCollection的=新CustomClassCollection
{
CustomClass =新的List＆LT; CustomClass＆GT;
{
新CustomClass
{
ID = 1，
描述=说明1
}，
新CustomClass
{
ID = 2，
描述=描述2
}，
新CustomClass
{
ID = 3，
描述=说明3
}，
}
}
}
};
返回查看（VM）;
}
}
和视图：
＆LT;％= Html.DropDownListFor（
X =＆GT; x.SelectedId，
新的SelectList（Model.Detail.MyCollection.CustomClass，ID，说明）
）％GT;
你有什么才能定义ASP.NET MVC IUS一个下拉列表，你需要两件事情就明白了：
- 要（在我的例子
SelectedId）选择的值绑定一个标量属性 - 要在列表中绑定（
Model.Detail.MyCollection.CustomClass中的例子）集合
I am trying to create a dropdown list to display all the value in a custom collection class such as
public class MyCustomClassCollection
{
public List<MyCustomClass> {get;set;}
}
I want it to show the Description:string of each MyCustomClass
I tried
<%: Html.DropDownList "Description", MyCustomClass %>
Resharper suggests that I cast MyCustomClass to IEnemerable
but the server returns an unable to cast error.
Any Idea how I can create this DropDownList?
__Modification___
public class ViewModel
{
public Detail detail { get; set; }
}
public class Detail //Inherited from webservce
{
public CustomClassCollection {get;set;}
.... Other Properties, a.k.a Custom Classes
}
public class CustomClassCollection
{
public List<CustomClass> {get;set;}
}
public class CustomClass {
public int Id {get;set;}
public string Description{get;set;}
... other properties
}
public ActionResult Index(int? id, DateTime? date)
{
if (id.Equals(null))
id = ######### ;
if (date.Equals(null))
date = DateTime.Today;
var vm = new ViewModel
{
Detail = _repository.Detail((int)id,(DateTime)date)
};
return View(vm);
}
The second argument of the DropDownList helper must be an IEnumerable<SelectListItem> or a SelectList which implements this interface for that matter. So in your controller action organize in such a way that you convert your custom collection into an IEnumerable<SelectListItem>. As always you could start by writing a view model:
public class MyViewModel
{
public string SelectedDescription { get; set; }
public SelectList Descriptions { get; set; }
}
and then have your controller action query the custom list and populate the view model which will be passed to the view:
public ActionResult Index()
{
var descriptions = yourCustomCollection.MyCustomClass.Select(x => new
{
Value = x.Description,
Text = x.Description
});
var model = new MyViewModel
{
Descriptions = new SelectList(descriptions, "Value", "Text")
};
return View(model);
}
and finally in your strongly typed view:
<%= Html.DropDownListFor(x => x.SelectedDescription, Model.Decriptions) %>
UPDATE:
After posting your updated models (which by the way are still incomplete and impossible to compile as you haven't provided any property names), here's an example:
public class ViewModel
{
public int SelectedId { get; set; }
public Detail Detail { get; set; }
}
public class Detail
{
public CustomClassCollection MyCollection { get; set; }
}
public class CustomClassCollection
{
public List<CustomClass> CustomClass { get; set; }
}
public class CustomClass
{
public int Id { get; set; }
public string Description { get; set; }
}
public class HomeController : Controller
{
public ActionResult Index()
{
var vm = new ViewModel
{
Detail = new Detail
{
MyCollection = new CustomClassCollection
{
CustomClass = new List<CustomClass>
{
new CustomClass
{
Id = 1,
Description = "description 1",
},
new CustomClass
{
Id = 2,
Description = "description 2",
},
new CustomClass
{
Id = 3,
Description = "description 3",
},
}
}
}
};
return View(vm);
}
}
and in the view:
<%= Html.DropDownListFor(
x => x.SelectedId,
new SelectList(Model.Detail.MyCollection.CustomClass, "Id", "Description")
) %>
What you have to understand in order to define a dropdown list in ASP.NET MVC ius that you need 2 things:
- A scalar property to bind the selected value to (
SelectedIdin my example) - A collection to bind the list to (
Model.Detail.MyCollection.CustomClassin the example)
这篇关于在MVC3创建下拉列表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！
