The following Window Messages (WM_) are raised as a result of input through the keyboard (or, sometimes, the mouse).
WM_CHAR | WM_DEADCHAR | WM_HOTKEY | WM_KEYDOWN | WM_KEYUP | WM_SYSCHAR | WM_SYSDEADCHAR | WM_SYSKEYDOWN | WM_SYSKEYUP
Posted to the window with the keyboard focus when a WM_KEYDOWN message is translated by the TranslateMessage function.
wparam value: The character ASCII Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Set if ALT key pressed at the same time. |
| Bit 30 | Set if this is a repeat of a previous key press. |
| Bit 31 | Set if the key is being released. |
A character code generated by a dead key which is posted to the window with the keyboard focus when a WM_KEYUP message is translated by the TranslateMessage function. A dead key is a key that generates a character, such as the umlaut (double-dot), that is combined with another character to form a composite character. For example, the umlaut-O character (Ö) is generated by typing the dead key for the umlaut character, and then typing the O key.
wparam value: The character ASCII Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Set if ALT key pressed at the same time. |
| Bit 30 | Set if this is a repeat of a previous key press. |
| Bit 31 | Set if the key is being released. |
Posted when the user presses a hot key registered by the RegisterHotKey function.
wparam value: The identifier of the hot key that generated the message. If the message was generated by a system-defined hot key, this parameter will be one of the following values: IDHOT_SNAPDESKTOP (-2) or IDHOT_SNAPWINDOW (-1).
lparam value:
| Bits 0-15 | The Scan Code‡ of the non-'hotkey' pressed. |
| Bits 16-31 | The hotkey(s) defined as: |
| MOD_ALT($0001) - Either of the Alt keys was pressed. | |
| MOD_CONTROL($0002) - Either of the Ctrl keys was pressed. | |
| MOD_SHIFT($0004) - Either of the Shift keys was pressed. | |
| MOD_WIN($0008) - Either of the Windows keys was pressed. | |
Posted to a window when a non-system key† is pressed. WM_CHAR can be used instead to return the character ASCII/ANSI code.
wparam value: The character Key Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Always reset or 0. |
| Bit 30 | Set if this is a repeat of a previous key press. |
| Bit 31 | Always reset or 0. |
Posted to a window when a non-system key† is released.
wparam value: The character Key Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Always reset or 0. |
| Bit 30 | Always set or 1. |
| Bit 31 | Always set or 1. |
The product of WM_SYSKEYDOWN being passed through the TranslateMessage function, this returns details of the system key† which was pressed.
wparam value: The character ASCII Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Set if ALT key pressed at the same time. |
| Bit 30 | Set if this is a repeat of a previous key press. |
| Bit 31 | Set if the key is being released. |
Sent to the window with the keyboard focus when a WM_SYSKEYDOWN message is translated by the TranslateMessage function. WM_SYSDEADCHAR specifies the character code of a system dead key — that is, a dead key that is pressed while holding down the ALT key.
wparam value: The character ASCII Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Set if ALT key pressed at the same time. |
| Bit 30 | Set if this is a repeat of a previous key press. |
| Bit 31 | Set if the key is being released. |
Posted to a window when a system key† is pressed. WM_SYSCHAR can be used instead to return the character ASCII/ANSI code.
wparam value: The character Key Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Set if ALT key pressed at the same time. |
| Bit 30 | Set if this is a repeat of a previous key press. |
| Bit 31 | Always reset or 0. |
Posted to a window when a system key† is released.
wparam value: The character Key Code of the key pressed.
lparam value:
| Bits 0-15 | The Repeat Count - the number of times the keystroke is repeated due to the user keeping the key depressed. |
| Bits 16-23 | The Scan Code‡ of the key pressed. |
| Bit 24 | Set if Extended Key* is pressed. |
| Bits 25-28 | Reserved. |
| Bit 29 | Set if ALT key pressed at the same time. |
| Bit 30 | Always set or 1. |
| Bit 31 | Always set or 1. |
* Extended Keys are: the right ALT and the right 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.
† A system key event is triggered either by pressing F10, having the Alt key held down while pressing another key or when no window currently has the keyboard focus.
‡ The code for the actual key, not character, pressed on the keyboard which is then translated into a key code or ASCII value.
{Created by Sjouke Hamstra; Last updated: 12/05/14 by James Gaite}