MVC学习系列——RazorViewEngine扩展

       有时候，我们的项目涉及到多种风格，我们可以通过扩展RazorViewEngine，这样就可以保持后台代码不发生变化。

新建类ThemeViewEngine继承于RazorViewEngine

 public class ThemeViewEngine : RazorViewEngine
    {
        public ThemeViewEngine(string theme)
        {
            ViewLocationFormats = new[]
           {
                "~/Views/Themes/" + theme + "/{1}/{0}.cshtml",
                "~/Views/Themes/" + theme + "/Shared/{0}.cshtml"
            };

            PartialViewLocationFormats = new[]
            {
                "~/Views/Themes/" + theme + "/{1}/{0}.cshtml",
                "~/Views/Themes/" + theme + "/Shared/{0}.cshtml"
            };

            AreaViewLocationFormats = new[]
            {
                "~Areas/{2}/Views/Themes/" + theme + "/{1}/{0}.cshtml",
                "~Areas/{2}/Views/Themes/" + theme + "/Shared/{0}.cshtml"
            };

            AreaPartialViewLocationFormats = new[]
            {
                "~Areas/{2}/Views/Themes/" + theme + "/{1}/{0}.cshtml",
                "~Areas/{2}/Views/Themes/" + theme + "/Shared/{0}.cshtml"
            };
        }
    }

Global类中，注册这种引擎

  //不同风格
            if (!string.IsNullOrEmpty(ConfigurationManager.AppSettings["Theme"]))
            {
                var activeTheme = ConfigurationManager.AppSettings["Theme"];
                ViewEngines.Engines.Insert(0, new ThemeViewEngine(activeTheme));
            }

web.config配置具体风格：

<add key="Theme" value="China" />

项目文件结构：

View:

   America:

@{
    ViewBag.Title = "ShowTheme";
}

<h2>ShowTheme   America</h2>

  China:

@{
    ViewBag.Title = "ShowTheme";
}

<h2>ShowTheme   China</h2>

运行：

 public ActionResult ShowTheme()
        {
            return View();
        }

效果图: