Gridview中的复选框控制错误

Question

复选框控件始终为false，直到我选中gridview中的复选框;

CheckBox grouped = (CheckBox)GridView1.Rows[i].FindControl("CheckBox1");

ASPX

<asp:Label ID="Label4" runat="server" Text="<%# bind('id')%>">
</asp:Label> <asp:Label ID="Label2" runat="server" Text="<%# bind('news_category')%>" </asp:Label> 
<asp:RadioButton ID="RadioButton2" runat="server" /> 
    <asp:CheckBox ID="CheckBox1" runat="server" />