gridview控件实现全选功能

前台：

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" AutoGenerateColumns="False"
        DataKeyNames="AreaID" DataSourceID="SqlDataSource1">
        <Columns>
            <asp:BoundField DataField="AreaID" HeaderText="AreaID" ReadOnly="True" SortExpression="AreaID" />
            <asp:BoundField DataField="CityID" HeaderText="CityID" SortExpression="CityID" />
            <asp:TemplateField>
                <HeaderTemplate>
                    <asp:CheckBox ID="chkAll" runat="server" AutoPostBack="True" OnCheckedChanged="chkAll_CheckedChanged" />
                </HeaderTemplate>
                <ItemTemplate>
                    <asp:CheckBox ID="chkItem" runat="server" />
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>

后台：

 protected void chkAll_CheckedChanged(object sender, EventArgs e)
    {
        for (int i = 0; i < this.GridView1.Rows.Count; i++)
        {
            ((CheckBox)GridView1.Rows[i].FindControl("chkItem")).Checked = ((CheckBox)this.GridView1.HeaderRow.FindControl("chkAll")).Checked;
        }
    }