ASP.NET การ findcontrol ใน Datagrid อยากจะ Findcontrol ChkAll ใน datagrid1 ครับ เพื่อที่จะนำมาใช้งานในโปรแกรม

	<asp:datagrid id="Datagrid1" runat="server" Font-Size="XX-Small" Width="208px" Font-Names="Microsoft Sans Serif,MS Sans Serif, Tahoma, sans-serif"
									BorderStyle="Solid" PageSize="8" onPageIndexChanged="DBGrid1_Paging" AllowPaging="true" AutoGenerateColumns="False"
									BorderWidth="1px" HorizontalAlign="Center">
									<COLUMNS>
										<asp:templatecolumn>
											<HEADERTEMPLATE>
												<table style="FONT-SIZE: 7pt; FONT-FAMILY: 'Microsoft Sans Serif'" border="0" cellpadding="1"
													cellspacing="0" width="100%" bordercolor="#FF9900" bgcolor="#FF9933" align="center">
													<tr>
													    <td bgcolor="#FFCC00" width="7%">Check All <asp:CheckBox ID="ChkAll" runat="server"  /></td>
														<td bgcolor="#FFCC00" width="9%">AssetNo.</td>
														<td bgcolor="#FFCC00" width="12%">Name</td>
														<td bgcolor="#FFCC00" width="8%">Loc</td>
														<td bgcolor="#FFCC00" width="8%">Qty</td>
														<td bgcolor="#FFCC00" width="8%">Flag</td>
														<td bgcolor="#FFCC00" width="8%">Delete</td>
													</tr>
											</HEADERTEMPLATE>
											<ITEMTEMPLATE>
												<tr>	
												<td bgcolor="#FFFFFF"><asp:CheckBox ID="ChkRow" runat="server" /></td>
													<td bgcolor="#FFFFFF"><asp:Label ID="lblKey" runat="server" text='<%# Container.DataItem("FASSETNO") %>' ></asp:Label>
													<td bgcolor="#FFFFFF"><%# Container.DataItem("FASSETNM") %></td>
													<td bgcolor="#FFFFFF"><%# Container.DataItem("FLCNO") %></td>
													<td bgcolor="#FFFFFF" align="right">
														<asp:label Runat="server" ID="lblQTY" text='<%# toformat(Container.DataItem("FQTY"),"N") %>'>
														</asp:label></td>
													<td bgcolor="#FFFFFF" align="right">
														<asp:label Runat="server" ID="lblQEOH" text='<%# toformat(Container.DataItem("FItemNo"),"X") %>'>
														</asp:label></td>
														<td bgcolor="#FFFFFF"><asp:LinkButton id="lnkDelete" CommandName="Delete" runat="server" OnClientClick="javascript: return confirm('คุณต้องการลบข้อมูลใช่หรือไม่?')" 
														>Delete</asp:LinkButton></td>
												</tr>
											</ITEMTEMPLATE>
											<FOOTERTEMPLATE>
			</TABLE>
			</FooterTemplate> </asp:TemplateColumn> </Columns>
			<PAGERSTYLE HorizontalAlign="Center" Position="Top" PageButtonCount="5" Mode="NumericPages"></PAGERSTYLE>
			</asp:datagrid>