Type
  TNumEdit=class(TCustomEdit)
  private
     FInputError:TNotifyevent;
  Protected
    Function GetValue:integer;
    Procedure SetValue(Value:Integer);
    Procedure KeyPress(var Key:char);override;
 Public
   Constructor Create(Owner:TComponent);override;
 Published
   Property OnInputError:TNotifyEvent read FInputError write FInputError;
   Property Value:integer read GetValue write SetValue Default 0;
   Property AutoSelect;
   Property AutoSize;
  //.....and so on
end;
//------------------------------------------
Function TNumEdit.GetValue:integer;
begin
  Result:=StrToIntDef(Text,0);
End;
//------------------------------------------
Procedure TNumEdit.SetValue(Value:Integer);
Begin
  text:=IntToStr(Value);
End;
//------------------------------------------
Procedure TNumEdit.KeyPress(var Key:char);
Begin
  If Not(Key in ['0'..'9']) And Not(Key=#8) Then
  Begin
     Key:=#0;//Null
     If Assigned(FInputError) Then
        FInputError(Self);
   End
   else
       Inherited;
End;
//------------------------------------------