为什么能显示数据库中的数据，却无法更新和删除？

        <asp:GridView ID="GridView1" runat="server" AutoGenerateDeleteButton="True" AllowPaging="True" 
            AutoGenerateEditButton="True" DataSourceID="sqlDataSource" PageSize="8"
            <FooterStyle BackColor="White" ForeColor="#000066" />
            <RowStyle ForeColor="#000066" />
            <SelectedRowStyle BackColor="#669999" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="White" ForeColor="#000066" HorizontalAlign="Left" />
            <HeaderStyle BackColor="#006699" Font-Bold="True" ForeColor="White" />
        </asp:GridView>
        
        <asp:SqlDataSource ID="sqlDataSource" runat="server"
              SelectCommand="SELECT [Name], [ClassName], [Price] FROM [PT_Product]" 
              ConnectionString="<%$ ConnectionStrings:ZHECOMDBConnectionString %>" 
              InsertCommand="INSERT INTO [PT_Product] ([Name], [ClassName], [Price]) VALUES (@Name, @ClassName, @Price)"
              UpdateCommand="Update PT_Product set Name=@name,ClassName=@className,Price=@price where ProductId=@id"
              DeleteCommand="Delete PT_Product where ProductId=@id"
            >
            <InsertParameters>
                <asp:Parameter Name="Name" Type="String" />
                <asp:Parameter Name="ClassName" Type="String" />
                <asp:Parameter Name="Price" Type="Decimal" />
            </InsertParameters>
            <DeleteParameters>
                <asp:Parameter Name="id" Type="Double"/>
            </DeleteParameters>
            <UpdateParameters>
                <asp:Parameter Name="name" Type="string" />
                <asp:Parameter Name="classname" Type="string" />
                <asp:Parameter Name="price" Type="Double" />
                <asp:Parameter Name="id" Type="Double"/>
            </UpdateParameters>
        </asp:SqlDataSource>