求教关于局部刷新的问题

页面是这样的
在Updatepanle里面有一个gridview
gridview模板里面有一个textbox8
我想实现这个textbox8的onblur调用 TextBox8_TextChanged
而且还要局部刷新.请问怎么实现啊.
我想实现   <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager> <asp:GridView runat="server" AutoGenerateColumns="False" Width="995px" ID="Gridview1">
     <asp:TemplateField HeaderText="购买数量" HeaderStyle-Width="120px">
                        <EditItemTemplate>
                            <asp:TextBox ID="TextBox5" runat="server"></asp:TextBox>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                                <ContentTemplate>
                                    <div style="text-align: center;">
                                        <div style="float: left; margin-top: 5px; margin-left: 5px;">
                                            <asp:ImageButton ID="ImageButton2" Width="15px" Height="15px" runat="server" ImageUrl="~/Img/sc_.gif"
                                                CommandName="scjian" />
                                        </div>
                                        <div style="float: left; margin-left: 5px; margin-right: 5px;">
                                            <asp:TextBox ID="TextBox8" runat="server" Height="21px" Width="41px" OnTextChanged="TextBox8_TextChanged"
                                                Text='<%# Eval("buyNum") %>' ToolTip="商品数量"></asp:TextBox>
                                        </div>
                                        <div style="float: left; margin-top: 5px;">
                                            <asp:ImageButton ID="ImageButton1" Width="15px" Height="15px" runat="server" ImageUrl="~/Img/sc+.gif"
                                                CommandName="scjia" />
                                        </div>
                                    </div>
                                </ContentTemplate>
                            </asp:UpdatePanel>
                        </ItemTemplate>
                        <HeaderStyle Width="120px"></HeaderStyle>
                    </asp:TemplateField>
  </asp:GridView>
UpdatePanelonblur