本章將和大家分享如何在ASP.NET MVC中修改視圖的默認路徑。在此之前，首先我們要搞懂MVC它是怎么搜索視圖的。
先來看下Demo的目錄結構：
本Demo的Web項目為ASP.NET Web 應用程序（目標框架為.NET Framework 4.5） MVC項目。
了解MVC的人應該都知道，在Action中如果要返回一個頁面，那我們一般的做法都是去調用View方法，如下所示：
接下來我們就通過反編譯工具來看一下這個View方法里面到底都做了啥：
可以看到它最后返回的是 ViewResult 對象，我們繼續通過反編譯工具來看一下這個 ViewResult 類：
可以發現，它是從 base.ViewEngineCollection 中找默認視圖的，下面我們繼續通過反編譯工具找到 base.ViewEngineCollection ，如下所示：
可以看到，其實它返回的就是一個 ViewEngineCollection 視圖引擎集合，並且它的取值來自 ViewEngines.Engines ，我們點擊 Engines 往里找：
繼續點擊 _engines 往里找：
找到最后我們可以發現，其實 ViewEngines.Engines 里面存放的就是 new WebFormViewEngine() 和 new RazorViewEngine() 。
我們通過反編譯工具找到 RazorViewEngine 這個類，如下所示：
using System; namespace System.Web.Mvc { /// <summary>Represents a view engine that is used to render a Web page that uses the ASP.NET Razor syntax.</summary> public class RazorViewEngine : BuildManagerViewEngine { internal static readonly string ViewStartFileName = "_ViewStart"; /// <summary>Initializes a new instance of the <see cref="T:System.Web.Mvc.RazorViewEngine" /> class.</summary> public RazorViewEngine() : this(null) { } /// <summary>Initializes a new instance of the <see cref="T:System.Web.Mvc.RazorViewEngine" /> class using the view page activator.</summary> /// <param name="viewPageActivator">The view page activator.</param> public RazorViewEngine(IViewPageActivator viewPageActivator) : base(viewPageActivator) { base.AreaViewLocationFormats = new string[] { "~/Areas/{2}/Views/{1}/{0}.cshtml", "~/Areas/{2}/Views/{1}/{0}.vbhtml", "~/Areas/{2}/Views/Shared/{0}.cshtml", "~/Areas/{2}/Views/Shared/{0}.vbhtml" }; base.AreaMasterLocationFormats = new string[] { "~/Areas/{2}/Views/{1}/{0}.cshtml", "~/Areas/{2}/Views/{1}/{0}.vbhtml", "~/Areas/{2}/Views/Shared/{0}.cshtml", "~/Areas/{2}/Views/Shared/{0}.vbhtml" }; base.AreaPartialViewLocationFormats = new string[] { "~/Areas/{2}/Views/{1}/{0}.cshtml", "~/Areas/{2}/Views/{1}/{0}.vbhtml", "~/Areas/{2}/Views/Shared/{0}.cshtml", "~/Areas/{2}/Views/Shared/{0}.vbhtml" }; base.ViewLocationFormats = new string[] { "~/Views/{1}/{0}.cshtml", "~/Views/{1}/{0}.vbhtml", "~/Views/Shared/{0}.cshtml", "~/Views/Shared/{0}.vbhtml" }; base.MasterLocationFormats = new string[] { "~/Views/{1}/{0}.cshtml", "~/Views/{1}/{0}.vbhtml", "~/Views/Shared/{0}.cshtml", "~/Views/Shared/{0}.vbhtml" }; base.PartialViewLocationFormats = new string[] { "~/Views/{1}/{0}.cshtml", "~/Views/{1}/{0}.vbhtml", "~/Views/Shared/{0}.cshtml", "~/Views/Shared/{0}.vbhtml" }; base.FileExtensions = new string[] { "cshtml", "vbhtml" }; } /// <summary>Creates a partial view using the specified controller context and partial path.</summary> /// <returns>The partial view.</returns> /// <param name="controllerContext">The controller context.</param> /// <param name="partialPath">The path to the partial view.</param> protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath) { return new RazorView(controllerContext, partialPath, null, false, base.FileExtensions, base.ViewPageActivator) { DisplayModeProvider = base.DisplayModeProvider }; } /// <summary>Creates a view by using the specified controller context and the paths of the view and master view.</summary> /// <returns>The view.</returns> /// <param name="controllerContext">The controller context.</param> /// <param name="viewPath">The path to the view.</param> /// <param name="masterPath">The path to the master view.</param> protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath) { return new RazorView(controllerContext, viewPath, masterPath, true, base.FileExtensions, base.ViewPageActivator) { DisplayModeProvider = base.DisplayModeProvider }; } } }
你會驚奇的發現，上面描述的路徑就是我們MVC默認的視圖路徑。既然如此，那我們大概知道了，將來如果要做一些擴展（例如：修改MVC默認的視圖路徑），就可以從這個類入手。
話不多說，下面我們就重點來看下如何修改MVC默認的視圖路徑？
我們先來驗證下 ViewEngines.Engines 里面存放的到底是不是只有 new WebFormViewEngine() 和 new RazorViewEngine() ，如下所示：
通過調試 Global.asax 中 Application_Start 方法，我們可以發現 ViewEngines.Engines 里面存的確實只有 new WebFormViewEngine() 和 new RazorViewEngine() ，那么下面我們就可以大膽的去擴展了。
首先自定義一個Razor視圖引擎，如下所示：
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; namespace ViewEngineExtend.ViewEngineExtend { /// <summary> /// 自定義Razor視圖引擎 /// </summary> public class CustomRazorViewEngine : RazorViewEngine { #region 構造函數 public CustomRazorViewEngine() : this(null) { } public CustomRazorViewEngine(IViewPageActivator viewPageActivator) : base(viewPageActivator) { } #endregion 構造函數 public override ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache) { if (controllerContext.HttpContext.Request.UserAgent.Contains("Chrome")) { this.SetTheme("Chrome"); } else { this.SetTheme(""); //一定得有，因為只有一個Engines實例 } return base.FindView(controllerContext, viewName, masterName, useCache); } public override ViewEngineResult FindPartialView(ControllerContext controllerContext, string partialViewName, bool useCache) { if (controllerContext.HttpContext.Request.UserAgent.Contains("Chrome")) { this.SetTheme("Chrome"); } else { this.SetTheme(""); //一定得有，因為只有一個Engines實例 } return base.FindPartialView(controllerContext, partialViewName, useCache); } /// <summary> /// 設置主題（修改視圖的默認路徑） /// </summary> /// <param name="browser">瀏覽器</param> void SetTheme(string browser) { if (!string.IsNullOrEmpty(browser) && browser.Contains("Chrome")) { base.AreaViewLocationFormats = new string[] { "~/Areas/{2}/ChromeViews/{1}/{0}.cshtml", "~/Areas/{2}/ChromeViews/{1}/{0}.vbhtml", "~/Areas/{2}/ChromeViews/Shared/{0}.cshtml", "~/Areas/{2}/ChromeViews/Shared/{0}.vbhtml" }; base.AreaMasterLocationFormats = new string[] { "~/Areas/{2}/ChromeViews/{1}/{0}.cshtml", "~/Areas/{2}/ChromeViews/{1}/{0}.vbhtml", "~/Areas/{2}/ChromeViews/Shared/{0}.cshtml", "~/Areas/{2}/ChromeViews/Shared/{0}.vbhtml" }; base.AreaPartialViewLocationFormats = new string[] { "~/Areas/{2}/ChromeViews/{1}/{0}.cshtml", "~/Areas/{2}/ChromeViews/{1}/{0}.vbhtml", "~/Areas/{2}/ChromeViews/Shared/{0}.cshtml", "~/Areas/{2}/ChromeViews/Shared/{0}.vbhtml" }; base.ViewLocationFormats = new string[] { "~/ChromeViews/{1}/{0}.cshtml", "~/ChromeViews/{1}/{0}.vbhtml", "~/ChromeViews/Shared/{0}.cshtml", "~/ChromeViews/Shared/{0}.vbhtml" }; base.MasterLocationFormats = new string[] { "~/ChromeViews/{1}/{0}.cshtml", "~/ChromeViews/{1}/{0}.vbhtml", "~/ChromeViews/Shared/{0}.cshtml", "~/ChromeViews/Shared/{0}.vbhtml" }; base.PartialViewLocationFormats = new string[] { "~/ChromeViews/{1}/{0}.cshtml", "~/ChromeViews/{1}/{0}.vbhtml", "~/ChromeViews/Shared/{0}.cshtml", "~/ChromeViews/Shared/{0}.vbhtml" }; } else { base.AreaViewLocationFormats = new string[] { "~/Areas/{2}/Views/{1}/{0}.cshtml", "~/Areas/{2}/Views/{1}/{0}.vbhtml", "~/Areas/{2}/Views/Shared/{0}.cshtml", "~/Areas/{2}/Views/Shared/{0}.vbhtml" }; base.AreaMasterLocationFormats = new string[] { "~/Areas/{2}/Views/{1}/{0}.cshtml", "~/Areas/{2}/Views/{1}/{0}.vbhtml", "~/Areas/{2}/Views/Shared/{0}.cshtml", "~/Areas/{2}/Views/Shared/{0}.vbhtml" }; base.AreaPartialViewLocationFormats = new string[] { "~/Areas/{2}/Views/{1}/{0}.cshtml", "~/Areas/{2}/Views/{1}/{0}.vbhtml", "~/Areas/{2}/Views/Shared/{0}.cshtml", "~/Areas/{2}/Views/Shared/{0}.vbhtml" }; base.ViewLocationFormats = new string[] { "~/Views/{1}/{0}.cshtml", "~/Views/{1}/{0}.vbhtml", "~/Views/Shared/{0}.cshtml", "~/Views/Shared/{0}.vbhtml" }; base.MasterLocationFormats = new string[] { "~/Views/{1}/{0}.cshtml", "~/Views/{1}/{0}.vbhtml", "~/Views/Shared/{0}.cshtml", "~/Views/Shared/{0}.vbhtml" }; base.PartialViewLocationFormats = new string[] { "~/Views/{1}/{0}.cshtml", "~/Views/{1}/{0}.vbhtml", "~/Views/Shared/{0}.cshtml", "~/Views/Shared/{0}.vbhtml" }; //base.FileExtensions = new string[] //{ // "cshtml", // "vbhtml" //}; } } } }
接着修改 Global.asax 中 Application_Start 方法，將默認的 RazorViewEngine 替換成自定義的 CustomRazorViewEngine ，如下所示：
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.Optimization; using System.Web.Routing; using ViewEngineExtend.ViewEngineExtend; namespace ViewEngineExtend { public class MvcApplication : System.Web.HttpApplication { protected void Application_Start() { AreaRegistration.RegisterAllAreas(); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); //var viewEngineCollection = ViewEngines.Engines; ViewEngines.Engines.Clear(); ViewEngines.Engines.Add(new WebFormViewEngine()); ViewEngines.Engines.Add(new CustomRazorViewEngine()); //替換成自定義的Razor視圖引擎 } } }
此外，Demo中還准備了兩套視圖：
其中 ~/ChromeViews/Home/Index.cshtml 頁面代碼如下：
@{ ViewBag.Title = "Home Page"; } <h1>This is ChromeViews/Home/Index</h1>
其中 ~/Views/Home/Index.cshtml 頁面代碼如下：
@{ ViewBag.Title = "Home Page"; } <h1>This is Views/Home/Index</h1>
最后，我們分別使用 谷歌瀏覽器和IE瀏覽器 來訪問 /Home/Index 頁面，如下所示：
谷歌瀏覽器運行結果如下：
IE瀏覽器運行結果如下：
仔細觀察后你會發現同樣都是訪問 /Home/Index 頁面，但是這兩個瀏覽器的運行結果卻是不一樣的，說明我們的視圖引擎擴展成功了。
至此本文就全部介紹完了，如果覺得對您有所啟發請記得點個贊哦！！！
Demo源碼：
鏈接：https://pan.baidu.com/s/1TWVlsq98Sjt6qYOMXaTwCQ 提取碼：3nm2
此文由博主精心撰寫轉載請保留此原文鏈接：https://www.cnblogs.com/xyh9039/p/15240321.html
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