在使用DataGrid时，如果页面很长，可能需要用户自己来拉动滚动条，下面的例子实现了自动滚动的功能。其基本原理就是利用了LinkButton的锚点的功能，如果使用PushButton，那还必须自己添加锚点。另外必须弄明白的是Page的PostBack时的客户端脚本：
<![CDATA[
<script language="javascript">
<!--
function __doPostBack(eventTarget, eventArgument) {
var theform = document.Form1;
theform.__EVENTTARGET.value = eventTarget;
theform.__EVENTARGUMENT.value = eventArgument;
theform.submit();
}
// -->
</script>
]]>
这段脚本中__doPostBack函数有两个参数：第一个eventTarget是触发PostBack的控件的UniqueID；第二参数eventArgument是一个对象，包含PostBack的额外信息。因此我们使用UniqueID来作为锚点的值。
源代码如下：
查看例子
DataGridAutoScroll.ASPx
<![CDATA[
<%@ Page Language="<a href="http://dev.21tx.com/language/vb/" target="_blank">VB</a>" AutoEventWireup="false" Codebehind="DataGridAutoScroll.aspx.vb"
Inherits="aspx<a href="http://dev.21tx.com/web/" target="_blank">Web</a>.DataGridAutoScroll"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<title runat="server" id="mengxianhui"></title>
<meta name="GENERATOR" content="Microsoft Visual Studio.NET 7.0">
<meta name="CODE_LANGUAGE" content="Visual Basic 7.0">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<asp:DataGrid id="DataGrid1" runat="server" BorderColor="#CC9966" BorderStyle="None"
BorderWidth="1px" BackColor="White" CellPadding="4">
<SelectedItemStyle Font-Bold="True" ForeColor="#663399" BackColor="#FFCC66"></SelectedItemStyle>
<ItemStyle ForeColor="#330099" BackColor="White"></ItemStyle>
<HeaderStyle Font-Bold="True" ForeColor="#FFFFCC" BackColor="#990000"></HeaderStyle>
<FooterStyle ForeColor="#330099" BackColor="#FFFFCC"></FooterStyle>
<Columns>
<asp:EditCommandColumn ButtonType="LinkButton" UpdateText="Update"
CancelText="Cancel" EditText="Edit"></asp:EditCommandColumn>
</Columns>
<PagerStyle HorizontalAlign="Center" ForeColor="#330099" BackColor="#FFFFCC"></PagerStyle>
</asp:DataGrid>
</form>
</body>
</HTML>
]]>
代码：DataGridAutoScroll.aspx.vb
<![CDATA[
Imports System
Imports System.Web
Imports System.Web.UI.WebControls
Imports System.Collections
Imports System.Data
Imports System.Data.SqlClient
Public Class DataGridAutoScroll
Inherits System.Web.UI.Page
Protected WithEvents DataGrid1 As System.Web.UI.WebControls.DataGrid
Protected mengxianhui As New HtmlGenericControl()
#Region " Web Form Designer Generated Code "
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
End Sub
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
InitializeComponent()
End Sub
#End Region
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
mengxianhui.InnerText = "【孟宪会之精彩世界】之.NET开发者园地"
If Not Page.IsPostBack Then
DataGrid1.DataSource = CreateDataSource()
DataGrid1.DataBind()
Else
Dim startUpScript As String
startUpScript = "<script language=Javascript>location.href='#" _
& Request.Form("__EVENTTARGET") & "';</script>"
Me.RegisterStartupScript(Me.UniqueID & "StartUp", startUpScript)
End If
End Sub
Function CreateDataSource() As ICollection
Dim dt As DataTable
Dim dr As DataRow
Dim i As Integer
'创建 DataTable
dt = New DataTable()
dt.Columns.Add(New DataColumn("字符型值", GetType(String)))
dt.Columns.Add(New DataColumn("布尔型值", GetType(Boolean)))
dt.Columns.Add(New DataColumn("货币型值", GetType(Double)))
'示例数据
For i = 1 To 150
dr = dt.NewRow()
dr(0) = "Item " + i.ToString()
If (i Mod 2 <> 0) Then
dr(1) = True
Else
dr(1) = False
End If
dr(2) = 1.23 * (i + 1)
'向datatable添加 row
dt.Rows.Add(dr)
Next
'返回DataTable的DataView
CreateDataSource = New DataView(dt)
End Function
Private Sub DataGrid1_ItemDataBound(ByVal sender As Object, _
ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles DataGrid1.ItemDataBound
Select Case e.Item.ItemType
Case ListItemType.Item, ListItemType.AlternatingItem
Dim editButton As LinkButton = New LinkButton()
editButton = CType(e.Item.Cells(0).Controls(0), LinkButton)
editButton.Attributes.Add("name", "#" & editButton.UniqueID)
Case ListItemType.EditItem
Dim UpdateButton As LinkButton = New LinkButton()
UpdateButton = CType(e.Item.Cells(0).Controls(0), LinkButton)
UpdateButton.Attributes.Add("name", "#" & UpdateButton.UniqueID)
End Select
End Sub
Private Sub DataGrid1_EditCommand(ByVal source As Object, _
ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles DataGrid1.EditCommand
DataGrid1.EditItemIndex = e.Item.ItemIndex
DataGrid1.DataSource = CreateDataSource()
DataGrid1.DataBind()
End Sub
Private Sub DataGrid1_CancelCommand(ByVal source As Object, _
ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles DataGrid1.CancelCommand
DataGrid1.EditItemIndex = -1
DataGrid1.DataSource = CreateDataSource()
DataGrid1.DataBind()
End Sub
Private Sub DataGrid1_UpdateCommand(ByVal source As Object, _
ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles DataGrid1.UpdateCommand
DataGrid1.EditItemIndex = -1
DataGrid1.DataSource = CreateDataSource()
DataGrid1.DataBind()
End Sub
End Class
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