Delphi Programming Skill Bit

1. How to detect the status of inserts, CapsLock, NumLock, ScrollLock state keys

Delphi can invoke the Getkeyboardstate () function of the win API.

Constant Key Name

Vk_insert Znsert Key

Vk_numlock NUM LOCK key

Vk_capital Caps Lock key

Vk_scroll SCROLL Lock key

Each bit of the keyboard buffer has a specific format, for the state key, the lowest bit is 1 when the state key is on state, you can use the odd () function to determine the status of this bit, the following is a simple example please refer to. The example places a Timer control, a StatusBar State bar.

procedure TForm1.Timer1Timer(Sender: TObject);
var ks:tkeyboardstate;
begin
getkeyboardstate(ks);//检测键盘函数
if odd(ks[VK_NUMLOCK]) then
statusbar1.panels.items[0].text:=NUM
else
statusbar1.panels.items[0].text:=;
if odd(ks[VK_INSERT]) then
statusbar1.panels.items[1].text:=INSERT
else
statusbar1.panels.items[1].text:=;
if odd(ks[VK_CAPITAL]) then
statusbar1.panels.items[2].text:=CAPITAL
else
statusbar1.panels.items[2].text:= ;
if odd(ks[VK_SCROLL]) then
statusbar1.panels.items[3].text:=SCROLL
else
statusbar1.panels.items[3].text:=;
end;
end.

2. Screen System Key

Maybe you want the program to not have the user press the System button Alt-tab or Ctrl-alt-del at run time, then you can use the following procedures to screen these keys.

procedure TForm1.FormCreate(Sender: TObject); 　 var tmp,Flag :integer;
begin
　 tmp := 0;
Flag := 1;
　 //屏蔽 Alt-Tab
　 SystemParametersInfo( SPI_SETFASTTA-SKSWITCH, Flag, @tmp, 0);
　 //屏蔽 Ctrl-Alt-Del
　 SystemParametersInfo( SPI_SCREENSAVERRU-NNING,Flag, @tmp, 0); 　
end;
　　 当你要恢复功能键时用以下代码:
Flag := 0;
SystemParametersInfo(SPI_SCREENSAVERRU-NNING,Flag,@temp,0);