恢复当前窗口的程序，由于当前进程有可能在全屏模式下运行，所以需要通过指定特定的热键使程序窗口消失，且不出现在任务栏上。下面介绍如何用Delphi实现。主要需要解决两个问题，即隐藏窗口和设定热键。
一. 隐藏窗口
通过API函数GETACTIVEWINDOW获取当前窗口；函数ShowWindow(HWND,nCmdShow)的参数nCmdShow取SW_HIDE时将之隐藏，取SW_SHOW时将之显示。例如：showwindow(getactivewindow,sw_hide)。隐藏好窗体后，须记住窗体句柄以便恢复。
（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）二. 键盘监控
为了实现键盘监控须用到钩子。
以下是程序的源文件：
---HKHide.pas---unit HKHide;interfaceuses Windows, Messages, sysutils;var hNextHookHide: HHook; HideSaveExit: Pointer; hbefore:longint;function KeyboardHookHandler(iCode: Integer;wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall; export;function EnableHideHook: BOOL; export;function DisableHideHook: BOOL; export;procedure HideHookExit; far;implementationfunction KeyboardHookHandler(iCode: Integer;wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall; export;const _KeyPressMask = $80000000;var f:textfile; temp:string;begin Result := 0; If iCode 0 Then begin Result := CallNextHookEx(hNextHookHide, iCode, wParam, lParam); Exit; end;// 侦测 Ctrl + Alt + F12 组合键 if ((lParam and _KeyPressMask) = 0) //按下时生效 and (GetKeyState(vk_Control) 0) and (getkeystate(vk_menu)0) and (wParam = vk_F12) then begin Result := 1; //文件不存在则创建 if not fileexists(c:test.txt) then begin assignfile(f,c:test.txt); rewrite(f); writeln(f,0); closefile(f); end else begin assignfile(f,c:test.txt); reset(f); readln(f,temp); hbefore:=strtoint(temp); begin hbefore:=getactivewindow; temp:=inttostr(hbefore); rewrite(f); writeln(f,temp); closefile(f); ShowWindow(hbefore, SW_HIDE); end else begin showwindow(hbefore,sw_show); rewrite(f); writeln(f,0); closefile(f); end; end; end;end;function EnableHideHook: BOOL; export;begin Result := False; if hNextHookHide 0 then Exit; // 挂上 WH_KEYBOARD 这型的 HOOK, 同时, 传回值必须保留下 // 来, 免得 HOOK 呼叫链结断掉 hNextHookHide := SetWindowsHookEx(WH_KEYBOARD, KeyboardHookHandler,HInstance,0); Result := hNextHookHide 0;end;function DisableHideHook: BOOL; export;begin if hNextHookHide 0 then begin Result:=True; UnhookWindowshookEx(hNextHookHide); // 解除 Keyboard Hook hNextHookHide:=0; end else Result:=False;end;procedure HideHookExit;begin // 如果忘了解除 HOOK, 自动代理解除的动作 if hNextHookHide 0 then DisableHideHook; ExitProc := HideSaveExit;end;end.---HKPHide.dpr---library HKPHide;uses HKHide in HKHide.pas;exports EnableHideHook, DisableHideHook;begin hNextHookHide := 0; hbefore:=0; HideSaveExit := ExitProc; ExitProc := @HideHookExit;end.文件制作好后选Build All编译成HKPHide.dll。新建一个工程Project1---Unit1.pas---unit Unit1;interfaceuses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;type TForm1 = class(TForm) Button1: TButton; Button2: TButton; procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); private { Private declarations } public { Public declarations } end;var Form1: TForm1;implementation{$R *.DFM}function EnableHideHook: BOOL; external HKPHide.DLL;function DisableHideHook: BOOL; external HKPHide.DLL;procedure TForm1.Button1Click(Sender: TObject);begin if EnableHideHook then ShowMessage(HotKey Testing...);end;procedure TForm1.Button2Click(Sender: TObject);begin if DisableHideHook then ShowMessage(HotKey Testing..., DONE!!);end;end.（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）运行程序按Button1后启动钩子，这时运行其他程序，按Ctrl+Alt+F12可将之隐藏，再按一下则恢复。以下程序在Delphi 4下通过。
