何时触发PageControl.PageControl1DrawTab事件？

Question

何时触发PageControl.PageControl1DrawTab事件？能否用该事件来改变TabSheet.caption区的颜色？

Answer 1

OwnerDraw 属性设为TRUE
procedure TForm1.PageControl1DrawTab(Control: TCustomTabControl;
  TabIndex: Integer; const Rect: TRect; Active: Boolean);
var
  cc: Cardinal;
  tabRect: TRect;
begin
  CopyRect(tabRect,Rect);
  Control.Canvas.Brush.Color:= Self.color;
  SetBkMode(Control.Canvas.Handle,1);
  Control.Canvas.FillRect(tabRect);
  cc  := SetTextAlign(Control.Canvas.Handle,TA_TOP);
  if(not Active) then
  begin
    SetTextColor(Control.Canvas.Handle,RGB(0,0,0));
    Control.Canvas.TextOut(tabRect.Left+5,Rect.Top+2,TPageControl(Control).Pages[TabIndex].Caption);
  end
  else
  begin
    SetTextColor(Control.Canvas.Handle,ColorToRGB(clBlue));
    Control.Canvas.TextOut(tabRect.Left+5,Rect.Top+4,TPageControl(Control).Pages[TabIndex].Caption);
  end;
  SetBkMode(Control.Canvas.Handle,0);
  SetTextAlign(Control.Canvas.Handle,cc);
end;