Hi Again,
i've tried something and found some codes from vfp help related INLIST() and below codes was solved my problem :) Thanks for the idea !

If Type("_Screen.ActiveForm.ActiveControl")=="O"  
  LOCAL loActiveControl
     m.loActiveControl = _Screen.ActiveForm.ActiveControl
	If m.loActiveControl.BaseClass = "Grid"
		If Inlist(nKeyCode, -1,-3,-5,-7,-8)
			Nodefault
			Return
		Endif
	Endif
Endif