ActiveHint在Delphi7与Delphi2007间差别
要实现的功能：在窗体上放一个CheckListBox控件，写OnMouseMove事件中动态显示鼠标滑动时鼠标位置所在项作为Hint显示出来。

现象：同一套代码在Delphi7上运行正常，但使用Delphi2007却没显示出Hint，跟没触发OnMouseMove事件一样，没任何效果，是为何？窗体控件CheckListBox的属性设置都一样(showHint=True)，Delphi7代码如下：

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, CheckLst;

type
TForm1 = class(TForm)
CheckListBox1: TCheckListBox;
procedure FormCreate(Sender: TObject);
procedure CheckListBox1MouseMove(Sender: TObject; Shift: TShiftState;
X, Y: Integer);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
checkListbox1.Items.Clear;
CheckListBox1.Items.Add('我是一个兵');
CheckListBox1.Items.Add('中华人民共和国中华人民共和国');
CheckListBox1.Items.Add('你好，英雄');
end;

procedure TForm1.CheckListBox1MouseMove(Sender: TObject;
Shift: TShiftState; X, Y: Integer);
var
idx: Integer;
begin
idx := CheckListBox1.ItemAtPos(Point(x, y), True);
if idx > -1 then
begin
CheckListBox1.Hint := CheckListBox1.Items[idx] ;
Application.ActivateHint(Point(x,y));
end;
end;

end.
[解决办法]

var
  hintWnd: THintWindow;

procedure TForm1.FormCreate(Sender: TObject);
begin
  chklst1.Items.Clear;
  chklst1.Items.Add('我是一个兵');
  chklst1.Items.Add('中华人民共和国中华人民共和国');
  chklst1.Items.Add('你好，英雄');


  ///////////////////////////////////////////////// 
 
  Application.CreateForm(HintWindowClass, hintWnd);
end;

procedure TForm1.chklst1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var
  idx: Integer;
  pt: TPoint;
  rect: TRect;
  hintStr: string;
begin
  GetCursorPos(pt);
  Inc(pt.X, 14);
  Inc(pt.Y, 12);
  idx := chklst1.ItemAtPos(Point(x, y), True);
  if idx > -1 then
  begin
    hintStr := chklst1.Items[idx];
    rect := hintWnd.CalcHintRect(180, hintStr, nil);
    OffsetRect(rect, pt.x, pt.y);
    hintWnd.Color := clInfoBk;
    hintWnd.ActivateHint(rect, hintStr);
  end
  else
    hintWnd.ReleaseHandle;
end;

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var
  pt: TPoint;
begin
  GetCursorPos(pt);
  if not PtInRect(chklst1.ClientRect, pt) then
    hintWnd.ReleaseHandle;
end;

[解决办法]
ActivateHint要求传的是屏幕坐标，所以把
Application.ActivateHint(Point(x,y));
改成
Application.ActivateHint(TControl(Sender).ClientToScreen(Point(x,y)));
就行了！