Dynamic Button's Event Not Working but Instead of that Dynamic link Button working fine

Hello ,
                  I have used dynamic button control On a page but the event of that control is not getting bind on a load and On a postback also. But Instead of that when i used to add the linkbutton On the same place the its working fine .
               I also add the Control in Init Event
          Dim btn As New Button        btn.ID = "btn" & i.string        btn.Text = "Book"
AddHandler btn.Click, AddressOf btn_Click
and for link button
 Dim lnkBtn As New linkbutton                 lnkBtn.ID = "btn" & & i.string   & ...