GridView item template linkbutton catch on code behind

<asp:TemplateField>

                  <ItemTemplate>

                        <asp:LinkButton ID = "lnkSil" runat="server" CommandName="bla"
CommandArgument='<%# ((GridViewRow) Container).RowIndex %>' Text= "Sil" ></asp:LinkButton>

                  </ItemTemplate>

                  </asp:TemplateField>

And I want to catch this from code behind and i used below code ;

((Button)e.Row.Cells[1].Controls[0]).Attributes.Add("onclick", "return confirm('Bu kaydi silmek istediginizden emin misiniz?')");

but I'm failed  how can i catch this controls on code behind like this 

also i tried 

((LinkButton)e.Row.Cells[1].Controls[0]).Attributes.Add("onclick", "return confirm('Bu kaydi silmek istediginizden emin misiniz?')");