给DataGrid添加CheckBox列、DataGrid列头CheckBox、全选按钮实现服务器端全选

全选按钮事件：
private void butAll_Click(object sender, System.EventArgs e)
  {
       System.Web.UI.WebControls.CheckBox CheckBox;
       if(butAll.Text=="全选")
       {
            foreach(DataGridItem DataGridItem in dg_list.Items)
            {
                 CheckBox=(CheckBox)DataGridItem.FindControl("CheckBox2");
                 CheckBox.Checked=true;
            }
            butAll.Text="全消";
       }
       else
       {
            foreach(DataGridItem DataGridItem in dg_list.Items)
            {
                 CheckBox=(CheckBox)DataGridItem.FindControl("CheckBox2");
                 CheckBox.Checked=false;
            }
            butAll.Text="全选";
          }
  }
DataGrid列头全选CheckBox事件：
private void dg_list_ItemCreated(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
  {
       if(e.Item.ItemType == ListItemType.Header)
       {
            CheckBox cbk=(CheckBox)e.Item.FindControl("CheckBox1");
            cbk.CheckedChanged+=new EventHandler(butAll_Click);
       }
  }