WinAPI: GetWindowThreadProcessId - 获取指定窗口的进程 ID 或线程 ID

//声明:
GetWindowThreadProcessId(
hWnd: HWND;                  {指定窗口句柄}
lpdwProcessId: Pointer = nil {返回进程 ID 的指针}
): DWORD;                      {返回线程 ID}

//举例:
unit Unit1;

interface

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

type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
c: Cardinal;
begin
GetWindowThreadProcessId(Handle, @c);
ShowMessage(IntToStr(c));                   {2792; 随机的}
{在本例中相同于 GetCurrentProcessID 的结果}
c := GetCurrentProcessID;
ShowMessage(IntToStr(c));                   {2792}

c := GetWindowThreadProcessId(Handle, nil);
ShowMessage(IntToStr(c));                   {2748}
{在本例中相同于 GetCurrentThreadID 的结果}
c := GetCurrentThreadID;
ShowMessage(IntToStr(c));                   {2748}
end;

end.