本章将和大家分享如何在ASP.NET MVC中修改视图的默认路径。在此之前，首先我们要搞懂MVC它是怎么搜索视图的。
先来看下Demo的目录结构：
本Demo的Web项目为ASP.NET Web 应用程序（目标框架为.NET Framework 4.5） MVC项目。
众所周知在Action中如果要返回一个页面，那我们一般的做法都是去调用View方法，如下所示：
接下来我们就通过反编译工具来看一下这个View方法里面到底都做了啥：
可以看到它最后返回的是 ViewResult 对象，我们继续通过反编译工具来看一下这个 ViewResult 类：
可以发现，它是从 base.ViewEngineCollection 中找默认视图的，下面我们继续通过反编译工具找到 base.ViewEngineCollection ，如下所示：
可以看到，其实它返回就是一个 ViewEngineCollection 视图引擎集合，并且它的取值来自 ViewEngines.Engines ，我们点击 Engines 往里找：
继续点击 _engines 往里找：
找到最后我们可以发现，其实 ViewEngines.Engines 里面存放的就是 new WebFormViewEngine() 和 new RazorViewEngine() 。
我们继续通过反编译工具找到 RazorViewEngine 这个类，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
};
}
}
}
可以惊奇的发现，上面描述的路径就是我们MVC默认的视图路径。既然如此，那我们大概知道了，将来如果要做一些扩展（例如：修改MVC默认的视图路径），就可以从这个类入手。
话不多说，下面我们重点来看下如何修改MVC默认的视图路径？
首先我们先来验证下 ViewEngines.Engines 里面存放的到底是不是只有 new WebFormViewEngine() 和 new RazorViewEngine() ，如下所示：
我们调试 Global.asax 中 Application_Start 方法，可以发现 ViewEngines.Engines 里面存的确实只有 new WebFormViewEngine() 和 new RazorViewEngine() ，那么下面我们就可以大胆的去扩展了。
自定义一个Razor视图引擎，如下所示：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
namespace ViewEngineExtend.ViewEngineExtend
{
/// <summary>
/// 自定义Razor视图引擎
/// </summary>
public class CustomRazorViewEngine : RazorViewEngine
{
#region 构造函数
public CustomRazorViewEngine()
: this(null)
{
}
public CustomRazorViewEngine(IViewPageActivator viewPageActivator)
: base(viewPageActivator)
{
}
#endregion 构造函数
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，因为只有一个Engines实例
}
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，因为只有一个Engines实例
}
return base.FindPartialView(controllerContext, partialViewName, useCache);
}
/// <summary>
/// 设置主题（修改视图的默认路径）
/// </summary>
/// <param name="browser">浏览器</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，将默认的 RazorViewEngine 替换成自定义的 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()); //替换成自定义的Razor视图引擎
}
}
}
此外，Demo中还准备了两套视图：
其中 ~/ChromeViews/Home/Index.cshtml 代码如下所示：
@{
ViewBag.Title = "Home Page";
}
<h1>This is ChromeViews/Home/Index</h1>
其中 ~/Views/Home/Index.cshtml 代码如下所示：
@{
ViewBag.Title = "Home Page";
}
<h1>This is Views/Home/Index</h1>
最后，我们分别使用 谷歌浏览器和IE浏览器 来访问 /Home/Index 页面，如下所示：
谷歌浏览器运行结果如下：
IE浏览器运行结果如下：
可以发现这两个浏览器的运行结果是不一样的，说明我们的视图引擎扩展成功了。
至此本文就全部介绍完了，如果觉得对您有所启发请记得点个赞哦！！！
Demo源码：
链接：https://pan.baidu.com/s/1TWVlsq98Sjt6qYOMXaTwCQ 提取码：3nm2
此文由博主精心撰写转载请保留此原文链接：https://www.cnblogs.com/xyh9039/p/15240321.html
版权声明：如有雷同纯属巧合，如有侵权请及时联系本人修改，谢谢！！！