delphi 使用WindowsAPI回调函数EnumWindowsProc获取系统窗口列表

{-----------------------------------------------------------------------------
作者：sushengmiyan 2013.02.28
备注：仅供学习交流使用
博客：http://blog.csdn.net/sushengmiyan
功能：枚举系统窗口
-----------------------------------------------------------------------------}
unit GetWinProcMainForm;
interface

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

type
  TForm1 = class(TForm)
    mmo: TMemo;
    btn1: TButton;
    procedure btn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form1: TForm1;
  
function EnumWindowsProc(hwnd: HWND; lParam: LPARAM): Boolean ;stdcall;

implementation

{$R *.dfm}

procedure TForm1.btn1Click(Sender: TObject);
begin
//　EnumWindows　专用的回调函数的格式:
// function　EnumWindowsProc(
// hwnd:　HWND;　　　　{找到的窗口句柄}
// lParam:　LPARAM　　　{EnumWindows　传给的参数;　因为它是指针,　可传入,　但一般用作传出数据}
// ):　Boolean;　stdcall;　{函数返回　False　时,　调用它的　EnumWindows　将停止遍历并返回　False}
   Form1.mmo.Clear;
   EnumWindows(@EnumWindowsProc ,0);
end;

function EnumWindowsProc(hwnd: HWND; lParam: LPARAM): Boolean ;stdcall;
var
  WindowText   : string  ;       // 窗体标题
 begin
  if ( IsWindowVisible(hwnd) or IsIconic(hwnd) ) and
       (
        (GetWindowLong(hwnd, GWL_HWNDPARENT) = 0) or
        (GetWindowLong(hwnd, GWL_HWNDPARENT) = Longint(GetDesktopWindow))
       )and
     ( GetWindowLong(hwnd, GWL_EXSTYLE) and WS_EX_TOOLWINDOW = 0 )  then
  {-----标题文字------}
  begin
    SetLength(WindowText, GetWindowTextLength(hwnd)+2);
    Getwindowtext(hwnd, Pchar(WindowText), GetWindowTextLength(hwnd)+2);
    WindowText := string( Pchar(WindowText));
    Form1.mmo.Lines.Add(WindowText);
  end;
  Result := True;
 end;
//　EnumWindows　的功能是遍历所有顶层窗口
// function　EnumWindows(
// lpEnumFunc:　TFNWndEnumProc;　{回调函数指针}
// lParam:　LPARAM　　　　　　　{给回调函数的参数,　它对应回调函数的第二个参数}
// ):　BOOL;　stdcall;　//成功与否,　其实是返回了回调函数的返回值
end.