//hCalc是父窗口句柄，

//測(cè)試1: 試著找找新建程序主窗口的句柄
var
h: HWND;
begin
{現(xiàn)在我們知道窗口的標(biāo)題是: Form1,、窗口的類名是: TForm1}
h := FindWindow('TForm1', 'Form1');
ShowMessage(IntToStr(h));      {656180; 這是隨機(jī), 每次啟動(dòng)窗口肯定不一樣}

{假如不知道類名}
h := FindWindow(nil, 'Form1');
ShowMessage(IntToStr(h));      {656180}

{假如不知道標(biāo)題名}
h := FindWindow('TForm1', nil);
ShowMessage(IntToStr(h));      {656180}

{其實(shí)這個(gè)窗口的句柄不就是 Self.Handle 嗎}
ShowMessage(IntToStr(Handle)); {656180}
end;

//測(cè)試2: 找計(jì)算器窗口的句柄(先打開(kāi)計(jì)算器)
var
h: HWND;
begin
{如果不是簡(jiǎn)體中文系統(tǒng), 這樣可能不靈}
h := FindWindow(nil, '計(jì)算器');
ShowMessage(IntToStr(h)); {1508334}

{最好這樣, 但你得提前知道計(jì)算器窗口的類名是: SciCalc}
h := FindWindow('SciCalc', nil);
ShowMessage(IntToStr(h)); {1508334}
end;

http://blog.csdn.net/yanjiaye520/article/details/6543265

然后最大化：

PostMessage(hwnd,WM_SYSCOMMAND, SC_MINIMIZE,0); //最小化 
PostMessage(hwnd,WM_SYSCOMMAND, SC_MAXIMIZE,0);//最大化 
PostMessage(hwnd,WM_SYSCOMMAND, SC_CLOSE,0);//關(guān)閉