Asp.NET MVC Widget开发 - ViewEngine
在Asp.NET开发博客类系统，我们经常都会用到Widget，像在线好友、最近访问好友、最新留言等，关于Asp.NET MVC与Asp.NET视图的差异，这里不再说了，大家可去查一下，接下来我以“我的好友”列表来要介绍在Asp.NET MVC实现这一功能以及结构设计。
- 开发工具：VS 2010 EN
- 开发语言：Visual C#
- ASP.NET MVC 3
- Asp.NET MVC Widget - 设计
- Asp.NET MVC Widget - Controller控制器
- Asp.NET MVC Widget - ViewEngine
- Asp.NET MVC Widget - Mobile支持
- Asp.NET MVC Widget - Html.Widget扩展方法
关于ViewEngine这篇是Widgets实现的核心，这里需要自定义Asp.NET MVC的视图引擎，也就是让Asp.NET MVC视图引擎可以找到widgets中的文件。
直接访问会出现以下错误，提示找不到显示文件
由错误中也可以看到 Asp.NET MVC默认引擎搜索文件的目录
/Views/Widget/
/Views/Shared/
要寻找到"widgets"中的文件就必须要让视图引擎去"widgets"中搜索文件
如Friends: /widgets/Friends/
添加自定义视图引擎
1. 添加 "WidgetViewEngine.cs"，继承自BuildManagerViewEngine
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
namespace Widgets
{
public class WidgetViewEngine : BuildManagerViewEngine
{
internal static readonly string ViewStartFileName = " _ViewStart " ;
public WidgetViewEngine()
: this ( null )
{
}
public WidgetViewEngine(IViewPageActivator viewPageActivator)
: base (viewPageActivator)
{
AreaViewLocationFormats = new [] {
" ~/Areas/{2}/Views/{1}/{0}.cshtml " ,
" ~/Areas/{2}/Views/Shared/{0}.cshtml "
};
AreaMasterLocationFormats = new [] {
" ~/Areas/{2}/Views/{1}/{0}.cshtml " ,
" ~/Areas/{2}/Views/Shared/{0}.cshtml "
};
AreaPartialViewLocationFormats = new [] {
" ~/Areas/{2}/Views/{1}/{0}.cshtml " ,
" ~/Areas/{2}/Views/Shared/{0}.cshtml "
};
ViewLocationFormats = new [] {
" ~/Views/{1}/{0}.cshtml " ,
" ~/Views/Shared/{0}.cshtml "
};
MasterLocationFormats = new [] {
" ~/Views/{1}/{0}.cshtml " ,
" ~/Views/Shared/{0}.cshtml "
};
PartialViewLocationFormats = new [] {
" ~/{1}s/{0}/Widget.cshtml " ,
" ~/Views/{1}/{0}.cshtml " ,
" ~/Views/Shared/{0}.cshtml "
};
FileExtensions = new [] {
" cshtml "
};
}
protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath)
{
return new RazorView(controllerContext, partialPath,
layoutPath: null , runViewStartPages: false , viewStartFileExtensions: FileExtensions, viewPageActivator: ViewPageActivator);
}
protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath)
{
var view = new RazorView(controllerContext, viewPath,
layoutPath: masterPath, runViewStartPages: true , viewStartFileExtensions: FileExtensions, viewPageActivator: ViewPageActivator);
return view;
}
}
}
2. 添加AppStart_Widgets.cs，修改默认视图引擎
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Widgets;
[assembly: PreApplicationStartMethod( typeof (AppStart_Widgets), " Start " )]
namespace Widgets
{
public class AppStart_Widgets
{
public static void Start()
{
// Clear system default view engines
ViewEngines.Engines.Clear();
ViewEngines.Engines.Add( new WidgetViewEngine());
}
}
}
3. 添加Friend实体及测试数据
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace Widgets.Models
{
public class Friend
{
public int Id { get ; set ; }
public string Name { get ; set ; }
}
public class FriendsContext
{
public FriendsContext()
{
Friends = new List < Friend > () {
new Friend{Id = 1 ,Name = " zhang san " },
new Friend{Id = 2 ,Name = " li si " },
new Friend{Id = 3 ,Name = " wang wu " }
};
}
public IEnumerable < Friend > Friends { get ; private set ; }
}
}
4. 更改widgets/Friends/Widget.cshtml
@model IEnumerable < Widgets .Models.Friend >
@{
Layout = "~/widgets/_Layout.cshtml";
ViewBag.Title = "My friends";
}
< div class ="newsletter" >
< ul >
@foreach (var item in Model)
{
< li > @item.Name </ li >
}
</ ul >
</ div >
项目结构
其它代码详见源码中。
再次访问，便出现要的结果。
