扩展ASP.NET MVC的HtmlHelper

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20091210084905750
ASP.NET MVC 1.0里面提供了如下一组标准的HtmlHelper：

  • Html.ActionLink
  • Html.AntiForgeryToken
  • Html.AttributeEncode
  • Html.BeginForm
  • Html.BeginRouteForm
  • Html.CheckBox
  • Html.DropDownList
  • Html.Encode
  • Html.EndForm
  • Html.Equals
  • Html.GetHashCode
  • Html.GetType
  • Html.Hidden
  • Html.ListBox
  • Html.Password
  • Html.RadioButton
  • Html.RenderPartial
  • Html.RouteCollection
  • Html.RouteLink
  • Html.TextArea
  • Html.TextBox
  • Html.ToString
  • Html.ValidationMessage
  • Html.ValidationSummary
  • Html.ViewContext
  • Html.ViewData
  • Html.ViewDataContainer

它们分布在下面这些文件里：

FormExtensions.cs
InputExtensions.cs
LinkExtensions.cs
MvcForm.cs
SelectExtensions.cs
TextAreaExtensions.cs
ValidationExtensions.cs

随着工程的推进，需求的上升，很快便会发现这些方法是不够用的。因此我们需要对其进行扩充，扩充的方式很简单，我们创建一个Helpers\TestExtensions.cs文件，内容如下：

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
 
namespace MvcApplication1.Helper
{
public static class TestExtensions
{
 
public static string Type(this HtmlHelper helper ,int i)
{
switch (i)
{
case 1: return String.Format("分类一");
case 2: return String.Format("分类二");
default: return String.Format("未知");
}
}
 
}
}

然后在View (aspx)文件里导入命名空间

<%@ Import Namespace="MvcApplication1.Helper" %>

然后Visual Studio的智能感知就能够提示该方法了，我们就可以像使用默认提供的方法一样使用我们新添加的方法。
20091210090914984 

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<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<ienumerable<mvcApplication1.Models.Test>>" %>
<%@ Import Namespace="MvcApplication1.Helper" %>
<asp:Content ID="indexTitle" ContentPlaceHolderID="TitleContent" runat="server">
Home Page
</asp:Content>
 
<asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server">
<h2>TestExtensions</h2>
<table>
<tr>
<th></th>
<th>
Id
</th>
<th>
Title
</th>
<th>
Description
</th>
<th>
Type
</th>
</tr>
 
<% foreach (var item in Model) { %>
 
<tr>
<td>
<%= Html.ActionLink("Edit", "Edit", new { /* id=item.PrimaryKey */ }) %> |
<%= Html.ActionLink("Details", "Details", new { /* id=item.PrimaryKey */ })%>
</td>
<td>
<%= Html.Encode(item.Id) %>
</td>
<td>
<%= Html.Encode(item.Title) %>
</td>
<td>
<%= Html.Encode(item.Description) %>
</td>
<td>
<%= Html.Type(item.Type.Value) %>
 
 
</td>
</tr>
 
<% } %>
 
</table>
</asp:Content>

20091210090929859