//自定义视图引擎的实质是把数据模型(moudle)和模板(View)转换成html页面，输出到客户端
public class MyView:IView

    {

        string _viewPath;

        public MyView(string viewPath)

        {

            this._viewPath = viewPath;

        }

        public void Render(ViewContext viewContext, System.IO.TextWriter writer)

        {

            // 获取视图文件的原始内容

            string rawContents = File.ReadAllText(_viewPath);

            // 根据自定义的规则解析原始内容

            string parsedContents = Parse(rawContents, viewContext.ViewData);

            // 呈现出解析后的内容

            writer.Write(parsedContents);

        }

        private string Parse(string contents,ViewDataDictionary viewData)

        {

            // 对 {##} 之间的内容作解析

            return Regex.Replace

            (

                contents,

                @"\{#(.+)#\}",

                p => GetMatch(p, viewData)

            );

        }

         protected virtual string GetMatch(Match m, ViewDataDictionary viewData)

        {

            if (m.Success)

            {

                // 获取匹配后的结果，即 ViewData 中的 key 值，并根据这个 key 值返回 ViewData 中对应的 value

                string key = m.Result("$1");

                if (viewData.ContainsKey(key))

                {

                    return viewData[key].ToString();

                }

            }

            return string.Empty;

        }

    }

    public class MyViewEngine:VirtualPathProviderViewEngine

    {

        public MyViewEngine()

        {

            //自定义View路径格式

            base.ViewLocationFormats = new string[] {

               "~/Views/{1}/{0}.my", "~/Views/Shared/{0}.my"

            };

        }

        protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath)

        {

            return this.CreateView(controllerContext, partialPath, string.Empty);

        }


　　　　　//把请求转换成

        protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath)

        {

            var physicalPath = controllerContext.HttpContext.Server.MapPath(viewPath);

            return new MyView(physicalPath);

        }

    }