Asp.net2.0使用技巧---WebParts与用户控件

如果在网页的某些内容的表现方式一样,而且内容也一样,为了减少工作量,我们可以创建一个用户控件来重复使用,这样可以减少代码的维护。

一、下面就是WebuserControlContent.ascx的内容：

%@ Control Language="VB" AutoEventWireup="false" CodeFile="textcontent.ascx.vb" Inherits="textcontent" %>

<tr>

<table>

<tr>

</tr>

</table>

</td>

</tr>

<tr>

</td>

</tr>

<tr>

<asp:DataList ID="MainContent" runat="server" RepeatColumns="1">

<tr>

<asp:Image ID="Image1" runat="server" ImageUrl="~/images/s_img1.jpg" /></td>

</td>

</tr>

</table>

</ItemTemplate>

</asp:DataList>

</td>

</tr>

<tr>

</td>

</tr>

</table>

这里的做法是将页面中都出现的、与栏目相关的标记都设为服务器端控件，以便在使用时用程序进行动态的替换，如标题图片、标题图标、背景图片、内容列表和“更多”链接，都提炼成服务器控件来处理。

二、新建一个usercontrol.aspx文件，并往里面添加一个webpartmanager控件和Table，接下来从工具箱中拖放几个webpartzone，并修改其HeaderText属性，在webpartzone中插入几个webusercontrolcontent.ascx，其id分别为usercontrolcontenthufu、usercontrolcontentliuxinqushi、usercontrolcontentkexuegouyi，结果如下：

<%@ Page Language="VB" MasterPageFile="~/text.master" AutoEventWireup="false" CodeFile="text_default.aspx.vb" Inherits="text_default" %>

<%@ Register TagPrefix ="uc" TagName ="textcontent" Src ="~/textcontent.ascx" %>

<%@ Register TagPrefix="Nsquared2" Assembly="Nsquared2.Web" Namespace="Nsquared2.Web.UI.WebControls.WebParts"%>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">

<tr>

<Nsquared2:TemplatedWebPartZone ChromeTemplateFile="~/Chrome_templates/WebPartTemplate.chrome" LayoutOrientation="Vertical" ID="WebPartZone1" runat="server" HeaderText="内容列一">

<uc:textcontent ID="textcontenthufu" runat="server" title="护肤"/>

<uc:textcontent ID ="textcontentjiansheng" runat ="server" title="健身"/>

<uc:textcontent ID ="textcontentliuxinqushi" runat ="server" title="流行趋势"/>

</zonetemplate>

</Nsquared2:TemplatedWebPartZone>

</td>

<Nsquared2:TemplatedWebPartZone ChromeTemplateFile="~/Chrome_templates/WebPartTemplate.chrome" LayoutOrientation="Vertical" ID="WebPartZone2" runat="server" HeaderText="内容列二">

<uc:textcontent ID ="textcontentmeifa" runat ="server" title="美发"/>

<uc:textcontent ID ="textcontentmeirong" runat ="server" title="美容"/>

<uc:textcontent ID ="textcontentkexuegouyi" runat ="server" title="科学购衣"/>

</zonetemplate>

</Nsquared2:TemplatedWebPartZone>

</td>

</tr>

</table>

</asp:Content>

三、编写后台处理程序

Imports System.Data

Imports System.Data.SqlClient

Partial Class text_default

Inherits System.Web.UI.Page

Private _obj As Control = Nothing

Private controlID As String = ""

Sub GetChildControl(ByVal ParentControl As Control)

If ParentControl.HasControls Then

For Each ct1 As Control In ParentControl.Controls

If Not (ct1.ID Is Nothing) AndAlso ct1.ID.StartsWith(controlID, StringComparison.OrdinalIgnoreCase) Then

_obj = ct1

Return

End If

GetChildControl(ct1)

End If

End Sub

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

Dim classid As Integer() = {7, 1, 8, 2, 4, 5}

Dim columnname As String() = {"hufu", "jiansheng", "liuxinqushi", "meifa", "meirong", "kexuegouyi"}

Dim columntitle As String() = {"护肤", "健身", "流行趋势", "美发", "美容", "科学购衣"}

Dim conntxt As New SqlConnection

conntxt.ConnectionString = Application("conn")

conntxt.Open()

GetChildControl(Form)

Dim i As Integer = 0

While i < 6

_obj = Nothing

controlID = "textcontent" + columnname(i)

GetChildControl(Form)

If Not (_obj Is Nothing) Then

Dim contentUC As UserControl = CType(_obj, UserControl)

Dim td As HtmlTableCell

td = CType(contentUC.FindControl("contentfooter"), HtmlTableCell)

td.InnerHtml = "<a href='#'>" + "<img src='http://www.aspxclub.com/UploadFile/Material/1/1928.gif' alt='更多内容" + columntitle(i) + "...'/></a>"

Dim dl As DataList = CType(contentUC.FindControl("maincontent"), DataList)

Dim sqltxt As String = "select top 8 newsid,news_title,news_edittime from news where news_classid=" + classid(i).ToString + "order by news_edittime desc"

Dim cmdtxt As SqlCommand = New SqlCommand(sqltxt, conntxt)

Dim drtxt As SqlDataReader = cmdtxt.ExecuteReader

dl.DataSource = drtxt

dl.DataBind()

drtxt.Close()

End If

System.Math.Min(System.Threading.Interlocked.Increment(i), i - 1)

End While

conntxt.Close()

conntxt.Dispose()

End Sub