<asp:GridView ID="ProductList" runat="server" AllowSorting="True" 
        AutoGenerateColumns="False" DataKeyNames="ProductID" 
        DataSourceID="ObjectDataSource1">
        <Columns>
            <asp:BoundField DataField="ProductName" HeaderText="ProductName" 
                SortExpression="ProductName" />
            <asp:BoundField DataField="UnitPrice" HeaderText="UnitPrice" 
                SortExpression="UnitPrice" />
            <asp:BoundField DataField="CategoryName" HeaderText="CategoryName" 
                ReadOnly="True" SortExpression="CategoryName" />
            <asp:BoundField DataField="SupplierName" HeaderText="SupplierName" 
                ReadOnly="True" SortExpression="SupplierName" />
            <asp:CheckBoxField DataField="Discontinued" HeaderText="Discontinued" 
                SortExpression="Discontinued" />
        </Columns>
    </asp:GridView>
一个很基础的GridView控件,后代代码中的一部分是
   // Reference the Table the GridView has been rendered into
            Table gridTable = (Table)ProductList.Controls[0];查了MSDN,意思是索引是0的子控件?如何理解啊。ProductList.Controls[0]到底是什么