访问DataGrid自定义列的头部控件

各位前辈好,小弟新学.NET没多久,现在有个问题想请教各位:
在DataGrid中,小弟做了个模版列,里面放了个CheckBox用来选择所在的行,同时在该列的头部也有一个CheckBox,作为全部选择用。目前有一个需求需要从后台为头部的HeaderText赋值，但是我怎么也访问不到头部那个控件。下面是该自定义列的HTML代码：
<asp:TemplateColumn HeaderText="选择">
<ItemStyle HorizontalAlign="Center" Width="60px"></ItemStyle>
<HeaderTemplate>
选择
<asp:CheckBox id="ckbSelectAll" Runat="server" Visible="True"></asp:CheckBox>
</HeaderTemplate>
<ItemTemplate>
<asp:CheckBox id="ckbSelect" Runat="server"></asp:CheckBox>
</ItemTemplate>
</asp:TemplateColumn>也就是说我想访问ckbSelectAll这个控件，请问小弟应该怎么做？（比如把ckbSelectAll的Checked设为true）请各位前辈指点一下，不胜感激！

解决方案 »

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itemcreate,itemdatabound
if(e.item.itemtype == itemtype.Header )
{
//use findcontrol
}
在后台中用(CheckBox )FindControl("ckbSelectAll")可以获得控件，
然后(CheckBox )FindControl("ckbSelectAll").Checked=True即可
<%@ Page language="c#" Codebehind="DataGrid翻页多选.aspx.cs" AutoEventWireup="false" Inherits="bsTest2005_8_16.Samples.DataGrid翻页多选" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>DataGrid翻页多选</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
<script language="javascript">
function selectAll(obj)
{
var i = 3;
var cbname = "DataGrid1__ctl"+i+"_CheckBox1";//DataGrid里嵌套的CheckBox的id是有规律的，利用之
while(document.getElementById(cbname)!=null && ((checkSelected() && obj.checked) || !obj.checked))
{
    document.getElementById(cbname).checked = obj.checked;
selectOne(document.getElementById(cbname));
i = i+1;
cbname = "DataGrid1__ctl"+i+"_CheckBox1";
}

}

function selectOne(obj)
{
var curID = obj.parentElement.parentElement.cells[1].innerText;
var selectedID = document.getElementById('TextBox1').value;
if(obj.checked)
{
if(selectedID.indexOf(curID)<0)
{
    if(checkSelected(obj))
    {
document.getElementById('TextBox1').value = selectedID + curID + ',';
var count = new Number(document.getElementById('TextBox2').value);
document.getElementById('TextBox2').value = count + 1;
}
else
{
obj.checked = false;
}
}
}
else
{
if(selectedID.indexOf(curID)>-1)
{
var count = new Number(document.getElementById('TextBox2').value);
document.getElementById('TextBox2').value = count - 1;
}
document.getElementById('TextBox1').value = selectedID.replace(curID,'').replace(",,",",");

}
}

function checkSelected(obj)
{
var count1 = new Number(document.getElementById('TextBox2').value);
var count2 = new Number(document.getElementById('TextBox3').value);
if(count1 >= count2)
{
alert("您好，请选择不多于"+count2+"条记录");
return false;
}
else
{
return true;

}
}
</script>
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<TABLE id="Table1" style="Z-INDEX: 103; LEFT: 8px; POSITION: absolute; TOP: 8px" cellSpacing="0"
cellPadding="0" width="80%" border="0">
<TR>
<TD>隐藏域：
<asp:TextBox id="TextBox1" runat="server"></asp:TextBox>
<asp:TextBox id="TextBox2" runat="server" Width="40px">0</asp:TextBox></TD>
<TR>
<TD>最多选择
<asp:TextBox id="Textbox3" runat="server" Width="40px">4</asp:TextBox>条记录</TD>
</TR>
<TR id="tr1">
<TD id="td1">
<asp:DataGrid id="DataGrid1" runat="server" AutoGenerateColumns="False" PageSize="8" AllowPaging="True">
<Columns>
<asp:TemplateColumn>
<HeaderStyle HorizontalAlign="Center"></HeaderStyle>
<ItemStyle HorizontalAlign="Center"></ItemStyle>
<HeaderTemplate>
<asp:CheckBox id="CheckBoxAll" runat="server" Text="本页全选"></asp:CheckBox>
</HeaderTemplate>
<ItemTemplate>
<asp:CheckBox id="CheckBox1" runat="server"></asp:CheckBox>
</ItemTemplate>
</asp:TemplateColumn>
<asp:BoundColumn DataField="field1"></asp:BoundColumn>
<asp:BoundColumn DataField="field2"></asp:BoundColumn>
<asp:BoundColumn DataField="field3"></asp:BoundColumn>
</Columns>
</asp:DataGrid></TD>
</TR>
<TR>
<TD><asp:Button id="Button1" runat="server" Text="获得选中记录的id"></asp:Button></TD>
</TR>
</TABLE>
</form>
</body>
</HTML>
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;namespace bsTest2005_8_16.Samples
{
/// <summary>
/// DataGrid翻页多选的摘要说明。
/// </summary>
public class DataGrid翻页多选 : System.Web.UI.Page
{
        protected System.Web.UI.WebControls.TextBox TextBox1;
        protected System.Web.UI.WebControls.Button Button1;
        protected System.Web.UI.WebControls.TextBox TextBox2;
        protected System.Web.UI.WebControls.TextBox Textbox6;
        protected System.Web.UI.WebControls.TextBox Textbox3;
        protected System.Web.UI.WebControls.DataGrid DataGrid1;

        private void Page_Load(object sender, System.EventArgs e)
        {
            if(!IsPostBack)
                BindData();

            this.Button1.Attributes.Add("onclick","return confirm('您确认要删除所有选中的记录吗？');");
        }        private void BindData()
        {
            //模拟出一些原始数据绑定DataGrid
            DataTable dt1 = new DataTable();
            dt1.Columns.Add("field1");
            dt1.Columns.Add("field2");
            dt1.Columns.Add("field3");            Random radm = new Random();
            for(int i=1;i<30;i++)
                dt1.Rows.Add(new object[]{"id"+i.ToString(),(i+1)*(i+2)," ABC"+radm.Next(10000).ToString()});

            this.DataGrid1.DataSource=dt1;
            this.DataGrid1.DataBind();
        }        private void DataGrid1_PageIndexChanged(object source, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)
        {
            this.DataGrid1.CurrentPageIndex = e.NewPageIndex;
            BindData();
        }
        private void DataGrid1_ItemDataBound(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
        {
            if(e.Item.ItemType == ListItemType.Header)
            {
                CheckBox cb = e.Item.Cells[0].FindControl("CheckBoxAll") as CheckBox;
                cb.Attributes.Add("onclick","selectAll(this);");//本页全选或取消的脚本函数
            }
            if(e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
            {
                CheckBox cb = e.Item.Cells[0].FindControl("CheckBox1") as CheckBox;
                cb.Attributes.Add("onclick","selectOne(this);");//选中或取消当前行的脚本函数                //如果当前行已选，那么checkbox应该勾上
                string curID = e.Item.Cells[1].Text;
                if(this.TextBox1.Text.IndexOf(curID)>-1)
                    cb.Checked = true;
            }
        }        private void Button1_Click(object sender, System.EventArgs e)
        {
            string a = this.TextBox1.Text;
            if(a.Length>0)
            {
                string sql = "delete from table1 where id in ("+a.TrimEnd(',')+")";                System.Data.OleDb.OleDbConnection cnn = new System.Data.OleDb.OleDbConnection("连接字符串");
                System.Data.OleDb.OleDbCommand cm = new System.Data.OleDb.OleDbCommand(sql,cnn);
                cnn.Open();
                int deletedRowsCount = cm.ExecuteNonQuery();
                cnn.Close();
            }
        }
#region Web 窗体设计器生成的代码
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
//
InitializeComponent();
base.OnInit(e);
}

/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
            this.DataGrid1.PageIndexChanged += new System.Web.UI.WebControls.DataGridPageChangedEventHandler(this.DataGrid1_PageIndexChanged);
            this.DataGrid1.ItemDataBound += new System.Web.UI.WebControls.DataGridItemEventHandler(this.DataGrid1_ItemDataBound);
            this.Button1.Click += new System.EventHandler(this.Button1_Click);
            this.Load += new System.EventHandler(this.Page_Load);        }
#endregion }
}
private void DataGrid1_ItemDataBound(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
{
if(e.Item.ItemType==ListItemType.Header)
{
CheckBox ddl = (CheckBox )e.Item.FindControl("ckbSelectAll");
ddl.Text ="";
}
}