WindowFromPoint- 获取指定点所在窗口的句柄

//声明:
WindowFromPoint(Point: TPoint): HWND;


//举例:
unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Timer1: TTimer;
    procedure Timer1Timer(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

var
  h: HWND;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  pt: TPoint;
  arr: array[0..254] of Char;
begin
  if GetCursorPos(pt) then             {如果能获取点}
  begin
    h := WindowFromPoint(pt);          {返回句柄}
    GetClassName(h, arr, Length(arr)); {获取该句柄窗口的类名}
    Text := arr;                       {显示在标题}
  end;
end;

end.