How can I detect special key presses?

How can I detect special key presses?

Applies To: C++Builder 1 or higher
Category: Knowledge Base

As described in How can I detect character key presses?, I can check the state of character keys. But what about other keys such as Enter, Tab or Ctrl?

Start a new project using File | New Application.

Double-click the OnKeyDown event:

void __fastcall TForm1::FormKeyDown(TObject *Sender, WORD &Key,

TShiftState Shift)

{

if(Key == VK_RETURN)

ShowMessage("You pressed Enter");

}

While the OnKeyPress event is designed only for ASCII keys, the OnKeyDown event lets you trap all the possible keys. To check, the name of a key, you'll need to use virtual-key codes. For more information, open the Win32 Programmer's Reference help file and go to the section Virtual-Key Codes.

Virtual-key codes

· VK_LBUTTON: Left mouse button

· VK_RBUTTON: Right mouse button

· VK_CANCEL: Control-break processing

· VK_MBUTTON: Middle mouse button (three-button mouse)

· VK_BACK: BACKSPACE key

· VK_TAB: TAB key

· VK_RETURN: ENTER key

· VK_SHIFT: SHIFT key

· VK_CONTROL: CTRL key

· VK_MENU: ALT key

· VK_PAUSE: PAUSE key

· VK_CAPITAL: CAPS LOCK key

· VK_SPACE: SPACEBAR

· VK_PRIOR: PAGE UP key

· VK_NEXT: PAGE DOWN key

· VK_END: END key

· VK_HOME: HOME key

· VK_LEFT: LEFT ARROW key

· VK_UP: UP ARROW key

· VK_RIGHT: RIGHT ARROW key

· VK_DOWN: DOWN ARROW key