GridView 选择框里的Checked值都是false
aspx里的：
<asp:GridView ID="GridView1" runat="server" Width="100%" CellPadding="0" ForeColor="#333333"
  AutoGenerateColumns="False" AllowPaging="true" PageSize="12" BorderColor="Silver"
  BorderStyle="Solid" BorderWidth="1px" OnRowDataBound="GridView1_RowDataBound"
  EmptyDataText="没有数据记录！！" DataKeyNames="id" AllowSorting="True">
  <Columns>
  <asp:TemplateField HeaderText="选择">
  <HeaderTemplate>
  <asp:CheckBox ID="chkAll" runat="server" ToolTip="全选" onclick="chkAll_Click(this)"
  Text="分店名称" />
  </HeaderTemplate>
  <ItemTemplate>
  <asp:CheckBox ID="chkItem" runat="server" ToolTip="选择" Text='<%# Eval("d_name")%>' onclick="chkItem_Click(this)" />
  </ItemTemplate>
  </asp:TemplateField>
  <asp:BoundField HeaderText="状态" DataField="zt" />
  <asp:BoundField HeaderText="单号" DataField="yewu_id" />
  <asp:BoundField HeaderText="地址" DataField="addr" />
  <asp:BoundField HeaderText="希望日期" DataField="xw_date" DataFormatString="{0:yyyy-MM-dd}" />
  <asp:BoundField HeaderText="机型" DataField="ji_x" />
  <asp:BoundField HeaderText="故障描述" DataField="g_z" />
   
  </Columns>
  <RowStyle BackColor="#F7F6F3" ForeColor="#284775" HorizontalAlign="Left" />
  <EditRowStyle BackColor="#999999" />
  <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
  <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
  <AlternatingRowStyle BackColor="#A4D3EE" ForeColor="#333333" />
  <PagerSettings Visible="False" />
  <HeaderStyle Font-Bold="False" Font-Italic="False" Font-Size="12px" Height="25px"
  BackColor="#8DB6CD" HorizontalAlign="Center" />
  </asp:GridView>

CS里的
protected void Button2_Click(object sender, EventArgs e)
  {
  for (int i = 0; i < GridView1.Rows.Count; i++)
  {
  System.Web.UI.WebControls.CheckBox chk = (System.Web.UI.WebControls.CheckBox)GridView1.Rows[i].FindControl("chkItem");


  if (chk.Checked == true)
  {
  int ddsID = Convert.ToInt32(Gr