CodeGuru Home VC++ / MFC / C++ .NET / C# Visual Basic VB Forums Developer.com
Results 1 to 5 of 5

Thread: Keystrokes

  1. #1
    Guest

    Keystrokes

    I am having difficulty registering keystrokes in my win32 app. I am not using mfc, so I have the old winproc func with the large switch statement. The thing is, I can register the keystroke, ie. actually know its happening using WM_KEYDOWN, but I cannot work out which key is being pressed. How do I do this in windows?


  2. #2
    Join Date
    May 1999
    Location
    Sydney, Australia
    Posts
    420

    Re: Keystrokes

    Running the risk of getting sued by the might Microsoft corporation this is their documentation:

    The WM_KEYDOWN message is posted to the window with the keyboard focus when a nonsystem key is pressed. A nonsystem key is a key that is pressed when the ALT key is not pressed.


    WM_KEYDOWN
    nVirtKey = (int) wParam; // virtual-key code
    lKeyData = lParam; // key data




    Parameters
    nVirtKey
    Value of wParam. Specifies the virtual-key code of the nonsystem key.
    lKeyData
    Value of lParam. Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag, as shown in the following table. Value Description
    0–15 Specifies the repeat count for the current message. The value is the number of times the keystroke is auto-repeated as a result of the user holding down the key. If the keystroke is held long enough, multiple messages are sent. However, the repeat count is not cumulative.
    16–23 Specifies the scan code. The value depends on the original equipment manufacturer (OEM).
    24 Specifies whether the key is an extended key, such as the right-hand ALT and CTRL keys that appear on an enhanced 101- or 102-key keyboard. The value is 1 if it is an extended key; otherwise, it is 0.
    25–28 Reserved; do not use.
    29 Specifies the context code. The value is always 0 for a WM_KEYDOWN message.
    30 Specifies the previous key state. The value is 1 if the key is down before the message is sent, or it is 0 if the key is up.
    31 Specifies the transition state. The value is always 0 for a WM_KEYDOWN message.


    Return Values
    An application should return zero if it processes this message.

    Default Action
    If the F10 key is pressed, the DefWindowProc function sets an internal flag. When DefWindowProc receives the WM_KEYUP message, the function checks whether the internal flag is set and, if so, sends a WM_SYSCOMMAND message to the top-level window. The wParam parameter of the message is set to SC_KEYMENU.

    Remarks
    Because of the autorepeat feature, more than one WM_KEYDOWN message may be posted before a WM_KEYUP message is posted. The previous key state (bit 30) can be used to determine whether the WM_KEYDOWN message indicates the first down transition or a repeated down transition.

    For enhanced 101- and 102-key keyboards, extended keys are the right ALT and CTRL keys on the main section of the keyboard; the INS, DEL, HOME, END, PAGE UP, PAGE DOWN and arrow keys in the clusters to the left of the numeric keypad; and the divide (/) and ENTER keys in the numeric keypad. Other keyboards may support the extended-key bit in the lKeyData parameter.

    Sally


  3. #3
    Join Date
    Apr 1999
    Posts
    16

    Re: Keystrokes

    WM_KEYDOWN
    nVirtKey = (int) wParam;
    lKeyData = lParam;
    As followed, the wParam contains the Virtual Key,
    you can get the key by it.
    At the same time, use the GetKeyState() function to get the key state.
    You can also ues WM_SYSKEYDOWN and WM_CHAR.



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  





Click Here to Expand Forum to Full Width

Featured