How to get input from keyboard while not focussed Delphi

Question

I would like to know how to get keyboard input in my delphi application while its not focussed. The application i am programming is going to be taking a screenshot while i am in game.

I have wrote the screen capture code but i am missing this last piece any advice would be appreciated.

Answer 1

You can register a hotkey (using the RegisterHotKey and UnregisterHotKey functions) and use the WM_HOTKEY message to intercept when the key is pressed.

Try this sample

type
  TForm3 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
     procedure WMHotKey(var Message: TMessage); message WM_HOTKEY;
  end;

var
  Form3: TForm3;

implementation


{$R *.dfm}


{ TForm3 }

const
  SaveScreeenHK=666;

procedure TForm3.FormCreate(Sender: TObject);
begin
 RegisterHotKey(Handle, SaveScreeenHK , MOD_CONTROL, VK_F10);
end;

procedure TForm3.FormDestroy(Sender: TObject);
begin
  UnregisterHotKey(Handle, SaveScreeenHK);
end;

procedure TForm3.WMHotKey(var Message: TMessage);
begin
 //call your method here
end;