扩展ASP.NET MVC的HtmlHelper

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：

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");
            }
        }

    }
}

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" %>

1	<%@ 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。

<%@ 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>

<%@ 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>

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>

未完待续

To Be Continued

扩展ASP.NET MVC的HtmlHelper