[转]Asp.NET MVC Widget开发 - ViewEngine

本文转自：/article/5622752.html

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。



源码下载