Gridivew结合CheckBox控件,CheckBox1.Checked即使选中值也是为false，什么情况？

Question

int count = 0;
            int rownum = 0;
            for (int i = 0; i < gv1.Rows.Count; i++)
            {
                CheckBox ck = (CheckBox)gv1.Rows[i].FindControl("ck1");
                if (ck.Checked == true)          //此处选中后应为true才对！！！
                {
                    rownum = i;
                    count = count + 1;
                }
            }

Answer 1

<asp:GridView ID="gv1" runat="server" CssClass="leibiao_table" width="98%" 
            border="0" align="center" cellpadding="0" AutoGenerateColumns="False">
      <Columns>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:CheckBox ID="ck1" runat="server" />
                </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField DataField="alarm" HeaderText="状态" />
            <asp:BoundField DataField="product_type" HeaderText="类别" />
            <asp:BoundField DataField="title" HeaderText="产品名称" />
            <asp:BoundField DataField="product" HeaderText="产品说明" />
            <asp:BoundField DataField="weight" HeaderText="重量(g)" />
            <asp:BoundField DataField="Packing" HeaderText="包装规格" />
            <asp:BoundField DataField="flag" HeaderText="产品类型" />
            <asp:BoundField DataField="re" HeaderText="备注" />
            <asp:BoundField DataField="DeclareName" HeaderText="申报名称" />
            <asp:BoundField DataField="DeclareValue" HeaderText="申报价值" />
      </Columns>
    </asp:GridView>贴上aspx代码