TUpDown.OnClick Event

Occurs when the user clicks an arrow button.

Pascal

property OnClick: TNotifyEvent;

C++

__property TUDClickEvent OnClick;__property TNotifyEvent OnClick;

Description

Write an OnClick event handler to take specific action when the user clicks one of the arrow buttons. If the Associate property is not used to automatically update the text of an edit control when the value of Position changes, use the OnClick event handler to respond to changes just before the value of Position is changed.

The Button parameter specifies how the value of Position is about to change. When Button is btNext, the Up or Right arrow was clicked, and the value of Position is about to increase by Increment. When Button is btPrev, the Down or Left arrow was clicked, and the value of Position is about to decrease by Increment.

C++ Examples:

Copy Code

/*
This example requires a new TPageControl, as-is, with no new pages
created at design time, and a TUpDown control, also from the Win95
page of the component palette.  The form OnCreate event handler
adds several new TabSheet controls to the Page Control.  The 
UpDown1Click event handler fires when the user clicks the up or
down button on the TUpDown control.  The SelectNextPage method of
the Page Control goes forward the comparison (Button = btNext)
evaluates as true.  If Button is not btNext, the previous Tab Page
is selected.
*/
void __fastcall TForm1::FormCreate(TObject *Sender)
{
const
  TColor colorPalette[12] = {
    clRed, clGreen, clYellow, clBlue, clWhite, clFuchsia,
    clTeal, clNavy, clMaroon, clLime, clOlive, clPurple};
  for (int i = 0; i < 10; i++)
  {
    TTabSheet *page = new TTabSheet(PageControl1);
    page->PageControl = PageControl1;
    page->Caption = AnsiString("Page") + IntToStr(i);
    page->Brush->Color = colorPalette[i];
  }
}

void __fastcall TForm1::UpDown1Click(TObject *Sender, TUDBtnType Button)
{
  PageControl1->SelectNextPage(Button == btNext);
}

Delphi Examples:

Copy Code

{
This example requires a new TPageControl, as-is, with no new pages
created at design time, and a TUpDown control, also from the Win95
page of the component palette.  The form OnCreate event handler
adds several new TabSheet controls to the Page Control.  The 
UpDown1Click event handler fires when the user clicks the up or
down button on the TUpDown control.  The SelectNextPage method of
the Page Control goes forward the comparison (Button = btNext)
evaluates as true.  If Button is not btNext, the previous Tab Page
is selected.
}
procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
const
  colorPalette: Array[0..11] of TColor =
    (clRed, clGreen, clYellow, clBlue, clWhite, clFuchsia,
    clTeal, clNavy, clMaroon, clLime, clOlive, clPurple);
begin
  for i := 0 to 9 do
    with TTabSheet.Create(Self) do
    begin
      PageControl := PageControl1;
      Caption := 'TabSheet #' + IntToStr(i);
      Brush.Color := colorPalette[i];
    end;
end;

procedure TForm1.UpDown1Click(Sender: TObject; Button: TUDBtnType);
begin
  PageControl1.SelectNextPage(Button = btNext);
end;