返璞归真 asp.net mvc (4) - View/ViewEngine

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.Web.Mvc; 
using System.Web.Mvc.Ajax; 

using MVC.Models; 

namespace MVC.Controllers 
{ 
         public  class ViewDemoController : Controller 
        { 
                ProductSystem ps =  new ProductSystem(); 

ActionResult Details() ActionResult Details(int id) 
                { 
                        var product = ps.GetProduct(id); 

                         if (product ==  null) 
                        { 
                                return View( "NotFound"); 
                        } 
                         else 
                        { 
                                product.CategoriesReference.Load(); 

                                // 编辑 Product 的时候需要在一个 DropDownList 中选择其所对应的 Category, 所以这里要构造一个 SelectList 类型的 ViewData 
                                 if (product.Categories ==  null) 
                                        ViewData[ "CategoryList"] =  new SelectList( new CategeorySystem().GetCategory(),  "CategoryId",  "CategoryName"); 
                                 else 
                                        ViewData[ "CategoryList"] =  new SelectList( new CategeorySystem().GetCategory(),  "CategoryId",  "CategoryName", product.Categories.CategoryID); 

                                // ViewData 和 TempData 都可以向 View 传递数据，其中 TempData 是保存在 Session 中的，一次请求后此 Session 会被清除 
                                // 在 View 中使用的时候，ViewData[key] 或 TempData[key] 即可 
                                TempData[ "Temp"] =  "TempData"; 

                                return View( "Details", product); 
                        } 
                } 

                [AcceptVerbs(HttpVerbs.Post)] 
ActionResult Update() ActionResult Update(int id, FormCollection formValues) 
                { 
                        var product = ps.GetProduct(id); 

                        // 可以通过 UpdateModel, 让系统自动为属性赋值（通过反射的方式，取得对象的属性名称，然后和 Request 的 key 做匹配，匹配成功的则赋值） 
                        UpdateModel<Products>(product); 

                        // 通过以下的方式让 UpdateModel 只更新指定属性 
                        //  string[] allowedProperties =  new[] {  "ProductName",  "UnitPrice" }; 
                        // UpdateModel(product, allowedProperties); 

                        var category =  new CategeorySystem().GetCategory(int.Parse(Request.Form[ "Category"])); 
                        product.CategoriesReference.EntityKey = ps.CreateEntityKey( "Categories", category); 

                         if (!product.IsValid) 
                        { 
                                foreach (var validation  in product.GetValidation()) 
                                { 
                                        // 设置验证信息 
                                        ModelState.AddModelError(validation.PropertyName, validation.ErrorMessage); 
                                } 
                        } 
                         else 
                        { 
                                ps.Save(); 
                        } 

                        ViewData[ "CategoryList"] =  new SelectList( new CategeorySystem().GetCategory(),  "CategoryId",  "CategoryName", category.CategoryID); 

                        return View( "Details", product); 
                } 
        } 
} 

<%@ Page Title= "" Language="C# " MasterPageFile="~/Views/Shared/Site.Master " Inherits="System.Web.Mvc.ViewPage<MVC.Models.Products>" %> 

<asp:Content ID= "Content1" ContentPlaceHolderID= "TitleContent" runat= "server"> 
        Details 
</asp:Content> 
<asp:Content ID= "Content2" ContentPlaceHolderID= "MainContent" runat= "server"> 
        <style type= "text/css"> 
                .bold 
                {}{ 
                        font-weight: bold; 
                } 
        </style> 
        <h2> 
                Details</h2> 
        <%= Html.ValidationSummary( "输入信息有误") %> 
        <% Html.BeginForm( "Update",  "ViewDemo",  new { id = Model.ProductID }, FormMethod.Post); %> 
        <p> 
                <strong>ProductID:</strong> 
                <%= Html.Encode(Model.ProductID) %> 
        </p> 
        <p> 
                <label  for= "ProductName"> 
                        ProductName:</label> 
                <%= Html.TextBox( "ProductName", Model.ProductName,  new { style =  "color: blue;", @ class =  "bold" })%> 
                <%= Html.ValidationMessage( "ProductName",  "*") %> 
        </p> 
        <p> 
                <label  for= "Category"> 
                        Category:</label> 
                <%-- Html.ListBox() 和 Html.DropDownList() 需要 IEnumerable<SelectListItem> 类型的数据做数据源 --%> 
                <%= Html.DropDownList( "Category", ViewData[ "CategoryList"]  as SelectList)%> 
        </p> 
        <p> 
                <strong>UnitPrice:</strong> 
                <%= Html.Encode( string.Format( "{0:F2}", Model.UnitPrice))%> 
        </p> 
        <p> 
                <input type= "submit" value= "Save" /> 
        </p> 
        <p> 
                <%= TempData[ "Temp"]%> 
        </p> 
        <% Html.EndForm(); %> 
        <p> 
                <%=Html.RouteLink( "返回首页",  new { Controller =  "Home" })%> 
        </p> 

         
<%-- 需要使用 Web Form 方式的话，则在后置代码中继承 System.Web.Mvc.ViewPage 或 System.Web.Mvc.ViewPage<T> 即可-- %> 
         
         
<%--    
HtmlHelper 简要说明: 


可以用如下的方式生成 form 
using (Html.BeginForm()) { } 
using (Html.BeginRouteForm()) { } 
Html.BeginForm(); Html.EndForm(); 


可以使用 Html.ListBox(), Html.RadioButton() 之类的来生成 html 元素 


Html.ValidationMessage() - 指定的 ModelName 输入信息不合法时所输出的验证信息 
Html.ValidationSummary() - 汇总所有验证信息 
验证信息可以在 Action 中用 ModelState.AddModelError() 的方式来添加 
验证信息的样式通过样式表修改 .field-validation- error{} .input-validation- error {} .validation-summary-errors {} 


Html.Encode(); Html.AttributeEncode(); 用于对输出的内容做编码 


Html.RenderPartial() - 引入一个 Partial View 


Html.ActionLink() - 根据 Action 找目标 
Html.RouteLink() - 根据路由找目标 


Html.ViewContext - View 的上下文信息。包括 Controller, TempData, ViewData, 路由信息, HttpContext 等信息 
--%> 
</asp:Content>

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 

using System.Web.Mvc; 
using System.IO; 
using System.Text.RegularExpressions; 

namespace MVC 
{ 
        /**//// <summary> 
        /// 自定义的视图 
        /// 视图需要继承 IView 接口 
        /// </summary> 
         public  class MyView : IView 
        { 
                // 视图文件的物理路径 
                 private  string _viewPhysicalPath; 

MyView() MyView( string viewPhysicalPath) 
                { 
                        _viewPhysicalPath = viewPhysicalPath; 
                } 

                /**//// <summary> 
                /// 实现 IView 接口的 Render() 方法 
                /// </summary> 
void Render() void Render(ViewContext viewContext, TextWriter writer) 
                { 
                        // 获取视图文件的原始内容     
                         string rawContents = File.ReadAllText(_viewPhysicalPath); 

                        // 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); 
                } 


string Parse()  string Parse( string contents, ViewDataDictionary viewData) 
                { 
                        // 对 {##} 之间的内容作解析 
                        return Regex.Replace 
                        ( 
                                contents,    
                                 @"\{#(.+)#\}",    

delegate  string MatchEvaluator() delegate  string MatchEvaluator(Match match) 
                                p => GetMatch(p, viewData) 
                        ); 
                } 

virtual  string GetMatch() 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; 
                } 
        } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 

using System.Web.Mvc; 

namespace MVC 
{ 
        // MvcContrib 中提供了很多 ViewEngine, 还提供了以 asp.net mvc 框架为基础的一些额外的功能 
        // 地址：http://www.codeplex.com/MVCContrib 

        /**//// <summary> 
        /// 自定义的视图引擎 
        /// 视图引擎需要继承 IViewEngine 接口 
        /// VirtualPathProviderViewEngine 继承了 IViewEngine 接口，实现了根据指定的路径格式搜索对应的页面文件的功能（内用缓存机制） 
        /// </summary> 
         public  class MyViewEngine : VirtualPathProviderViewEngine 
        { 
MyViewEngine() MyViewEngine() 
                { 
                        // 自定义 View 路径格式 
                        base.ViewLocationFormats =  new  string[]    
                        {    
                                 "~/Views/{1}/{0}.my",  "~/Views/Shared/{0}.my"    
                        }; 
                } 

override IView CreatePartialView() override IView CreatePartialView(ControllerContext controllerContext,  string partialPath) 
                { 
                        return this.CreateView(controllerContext, partialPath,  string. Empty); 
                } 

                /**//// <summary> 
                /// 根据指定路径返回一个实现了 IView 接口的对象 
                /// </summary> 
override IView CreateView() override IView CreateView(ControllerContext controllerContext,  string viewPath,  stringmasterPath) 
                { 
                        var physicalPath = controllerContext.HttpContext.Server.MapPath(viewPath); 

                        return  new MyView(physicalPath); 
                } 
        } 
}

void Application_Start() void Application_Start() 
{ 
        // 增加新的视图引擎 ViewEngine 
        ViewEngines.Engines.Add( new MyViewEngine());     
}