<asp:SqlDataSource ID="SrcCats" runat="server" 
	ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>" 
	SelectCommand="SELECT * FROM [Categories]"></asp:SqlDataSource>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
	DataKeyNames="CategoryID" DataSourceID="SrcCats">
	<Columns>
		<asp:BoundField DataField="CategoryID" 
			HeaderText="CategoryID" 
			InsertVisible="False" 
			ReadOnly="True" 
			SortExpression="CategoryID" />
		<asp:TemplateField HeaderText="CategoryName" 
			SortExpression="CategoryName">
			<ItemTemplate>
				<asp:LinkButton ID="lnk" runat="server" 
					Text='<%# Bind("CategoryName") %>'
					OnClick="lnk_Click"
					OnClientClick="<%# GetClientClick() %>"
				/>
			</ItemTemplate>
		</asp:TemplateField>
		<asp:BoundField DataField="Description" 
			HeaderText="Description" 
			SortExpression="Description" />
	</Columns>
</asp:GridView>

Protected Function GetClientClick() As String
	Dim oDataItem As Object = Page.GetDataItem
	Dim rv As DataRowView = CType(oDataItem, DataRowView)
	Dim categoryName As String = rv("CategoryName").ToString
 
	Dim js As String = "alert('{0}')"
	js = String.Format(js, categoryName)
	Return js
End Function