Changing the Style to 2 - Dropdown List seems to work:

oform = CREATEOBJECT('testform')
oform.show
READ EVENTS

DEFINE CLASS testform AS form


   Height = 250
   Width = 493
   DoCreate = .T.
   Name = "TestForm"
   Caption = 'Test Form'
   DIMENSION myarray[5]


   ADD OBJECT combo1 AS combobox WITH ;
      MaxLength = 3, ;
      RowSourceType = 5, ;
      RowSource = "thisform.myarray", ;
      Height = 24, ;
      Left = 48, ;
      Style = 2, ;
      Top = 16, ;
      Width = 100, ;
      Format = "", ;
      BoundTo = .T., ;
      Themes = .T., ;
      Name = "Combo1"


   ADD OBJECT text1 AS textbox WITH ;
      Height = 23, ;
      Left = 168, ;
      ReadOnly = .T., ;
      TabStop = .F., ;
      Top = 16, ;
      Width = 100, ;
      Name = "Text1"


   ADD OBJECT text2 AS textbox WITH ;
      Height = 23, ;
      Left = 288, ;
      ReadOnly = .T., ;
      TabStop = .F., ;
      Top = 16, ;
      Width = 100, ;
      Name = "Text2"


   ADD OBJECT list1 AS listbox WITH ;
      RowSourceType = 5, ;
      RowSource = "thisform.myarray", ;
      Height = 156, ;
      Left = 48, ;
      SpecialEffect = 0, ;
      Top = 67, ;
      Width = 100, ;
      BoundTo = .T., ;
      Themes = .T., ;
      Name = "List1"


   ADD OBJECT text3 AS textbox WITH ;
      Height = 23, ;
      Left = 168, ;
      ReadOnly = .T., ;
      TabStop = .F., ;
      Top = 67, ;
      Width = 100, ;
      Name = "Text3"


   ADD OBJECT text4 AS textbox WITH ;
      Height = 23, ;
      Left = 288, ;
      ReadOnly = .T., ;
      TabStop = .F., ;
      Top = 67, ;
      Width = 100, ;
      Name = "Text4"


   ADD OBJECT label1 AS label WITH ;
      BackStyle = 0, ;
      Caption = "Value", ;
      Height = 17, ;
      Left = 168, ;
      Top = 52, ;
      Width = 40, ;
      Name = "Label1"


   ADD OBJECT label2 AS label WITH ;
      BackStyle = 0, ;
      Caption = "Value", ;
      Height = 17, ;
      Left = 168, ;
      Top = 0, ;
      Width = 40, ;
      Name = "Label2"


   ADD OBJECT label3 AS label WITH ;
      BackStyle = 0, ;
      Caption = "Display Value", ;
      Height = 17, ;
      Left = 288, ;
      Top = 0, ;
      Width = 96, ;
      Name = "Label3"


   ADD OBJECT label4 AS label WITH ;
      BackStyle = 0, ;
      Caption = "Display Value", ;
      Height = 17, ;
      Left = 288, ;
      Top = 52, ;
      Width = 96, ;
      Name = "Label4"


   PROCEDURE Init
      DODEFAULT()
      dimension thisform.myarray(5)
      thisform.myarray(1) = 1
      thisform.myarray(2) = 10
      thisform.myarray(3) = 100
      thisform.myarray(4) = 298
      thisform.myarray(5) = 999
      thisform.combo1.listindex = 1
      thisform.list1.listindex = 1
      thisform.text1.value = thisform.combo1.value
      thisform.text2.value = thisform.combo1.displayvalue
      thisform.text3.value = thisform.list1.value
      thisform.text4.value = thisform.list1.displayvalue
      thisform.refresh()
   ENDPROC


   PROCEDURE combo1.Click
      DODEFAULT()
      thisform.text1.value = thisform.combo1.value
      thisform.text2.value = thisform.combo1.displayvalue
      thisform.refresh()
   ENDPROC


   PROCEDURE list1.Click
      thisform.text3.value = thisform.list1.value
      thisform.text4.value = thisform.list1.displayvalue
      thisform.refresh()
   ENDPROC


   PROCEDURE DESTROY
      CLEAR EVENTS
   ENDPROC
   
ENDDEFINE

>I have a combobox. If I put a inputmax ( 999 ) to it, when select a value from list it doesn't appear on comboboxes text portion. But actually that value is attached. If I select value from keyboard or I remove inputmax value is displayed. I'm angry with that. I cannot found a solution... :(
>
>Update: I tried inputmask 999999999999 and value can display. Why? I don't want to any input more than 999