unit GSPageControl;
{©Drkb v.3(2007): www.drkb.ru}
interface
uses
 Windows, Messages, Types, SysUtils, Classes, Controls, ComCtrls, CommCtrl;
type
 TGSPageControl = class(TPageControl)
 private
  FNewPageIndex, FNotifyIndex: Integer;
  FTab:boolean;
 protected
  function GetTabFromCursor: Integer;
  function CanChange: Boolean; override;
  procedure WMKeyDown(var Message: TWMKey); message WM_KEYDOWN;
  procedure CMDialogKey(var Message: TCMDialogKey); message CM_DIALOGKEY;
 public
  property NewPageIndex: Integer read FNewPageIndex;
  constructor Create(AOwner: TComponent); override;
 end;
procedure Register;
implementation
procedure Register;
begin
 RegisterComponents('Samples', [TGSPageControl]);
end;
{ TGSPageControl }
function TGSPageControl.CanChange: Boolean;
begin
 if fTab then FNewPageIndex:=FNotifyIndex else
 FNewPageIndex := GetTabFromCursor;
 if FNewPageIndex = -1 then
  FNewPageIndex := FNotifyIndex;
 Result := inherited CanChange;
 FNewPageIndex := -1;
 fTab:=false;
end;
procedure TGSPageControl.CMDialogKey(var Message: TCMDialogKey);
begin
 fTab:=true;
 if (Focused or Windows.IsChild(Handle, Windows.GetFocus)) and
  (Message.CharCode = VK_TAB) and (GetKeyState(VK_CONTROL) < 0) then
  FNotifyIndex := FindPage(ActivePage, True, False).TabIndex;
 inherited;
end;
constructor TGSPageControl.Create(AOwner: TComponent);
begin
 inherited;
 FNotifyIndex := 0;
 FNewPageIndex := 0;
 FTab:=false;
end;
function TGSPageControl.GetTabFromCursor: Integer;
var
 HitTestInfo: TTCHitTestInfo;
 P: TPoint;
begin
 GetCursorPos(P);
 HitTestInfo.pt := Self.ScreenToClient(P);
 HitTestInfo.flags := TCHT_ONITEM;
 Result := SendMessage(Self.Handle, TCM_HITTEST, 0, Integer(@HitTestInfo));
end;
procedure TGSPageControl.WMKeyDown(var Message: TWMKey);
begin
 with Message do
  case Message.CharCode of
  37: FNotifyIndex := FindPage(ActivePage, False, False).TabIndex;
  39: FNotifyIndex := FindPage(ActivePage, True, False).TabIndex;
  end;
 inherited;
end;
end.

procedure TForm1.GSPageControl1Changing(Sender: TObject;
 var AllowChange: Boolean);
begin
 AllowChange:=GSPageControl1.Pages[GSPageControl1.NewPageIndex].Enabled
end;