Try to do the following
Add ImageButton inside the ItemTemplate of the Gridview
<asp:templatefield headertext="""" itemstyle-width=""2%"><br" mode="hold" xmlns:asp="#unknown" /> <ItemTemplate>
<asp:ImageButton runat="server"
CommandName='DeleteItem'
CommandArgument = '<%# Eval("ID") %>'
ImageUrl="";
</ItemTemplate>
In GridView OnItemCommand event
{
if(e.CommandName=="DeleteItem")
{
var id = Int32.Parse(e.CommandArgument);
}