WM_SYSCOMMAND
Notification
A window receives this message when the user chooses a command from the
Window menu (formerly known as the system or control menu) or when the
user chooses the maximize button, minimize button, restore button, or close
button.
Syntax
WM_SYSCOMMAND
WPARAM wParam
LPARAM lParam;
Parameters
- wParam
- Specifies the type of system command requested. This parameter can be one of
the following values.
- SC_CLOSE
- Closes the window.
- SC_CONTEXTHELP
- Changes the cursor to a question mark with a pointer. If the user then
clicks a control in the dialog box, the control receives a WM_HELP message.
- SC_DEFAULT
- Selects the default item; the user double-clicked the window menu.
- SC_HOTKEY
- Activates the window associated with the application-specified hot key. The
lParam parameter identifies the window to activate.
- SC_HSCROLL
- Scrolls horizontally.
- SC_KEYMENU
- Retrieves the window menu as a result of a keystroke. For more information,
see the Remarks section.
- SC_MAXIMIZE
- Maximizes the window.
- SC_MINIMIZE
- Minimizes the window.
- SC_MONITORPOWER
- Sets the state of the display. This command supports devices that have
power-saving features, such as a battery-powered personal computer.
The lParam parameter can have the following values:
1 - the display is going to low power
2 - the display is being shut off
- SC_MOUSEMENU
- Retrieves the window menu as a result of a mouse click.
- SC_MOVE
- Moves the window.
- SC_NEXTWINDOW
- Moves to the next window.
- SC_PREVWINDOW
- Moves to the previous window.
- SC_RESTORE
- Restores the window to its normal position and size.
- SC_SCREENSAVE
- Executes the screen saver application specified in the [boot] section of the
System.ini file.
- SC_SIZE
- Sizes the window.
- SC_TASKLIST
- Activates the Start menu.
- SC_VSCROLL
- Scrolls vertically.
- lParam(东西被点中时的鼠标位置,低位是光标的X轴坐标,高位是光标的Y轴坐标)
- The low-order word specifies the horizontal position of the cursor, in
screen coordinates, if a window menu command is chosen with the mouse.
Otherwise, this parameter is not used.
The high-order word specifies the vertical position of the cursor, in screen
coordinates, if a window menu command is chosen with the mouse. This parameter
is –1 if the command is chosen using a system accelerator, or zero if using a
mnemonic.