Win32 Windows Programming VI

WM_PAINT message

1 WM_PAINT A WM_PAINT message is generated due to the window's mutual coverage, and so on, resulting in areas that need to be drawn. In general, do not send WM_PAINT messages directly, through API declaration need to draw area to produce

WM_PAINT message

For example, you can use InvalidateRect to declare a region that needs to be redrawn

BOOL InvalidateRect (  hwnd  hwnd,           //Handle to Window  lpRect ,   Rectangle coordinates  BOOL  bErase          //Erase state);

2 wm_paint points of attention2.1 If there is more than one WM_PAINT message in a message queue, only the last message has a role2.2 WM_PAINT message processing, empty the area that needs to be drawn. Use of BeginPaint3 WM_PAINT3.1 WM_PAINT must be called at the beginning BeginPaint3.2 Wm_paint must be called at the end of the EndPaint
Keyboard messages

1 keyboard messages

Key message

Wm_keydown occurs when the key is pressed

Wm_keyup Occurs when a key is released

Wm_syskeydown (ALT/F10) occurs when the system key is pressed

Wm_syskeyup occurs when the System key is released

Character message

Wm_char occurs when a character key is pressed

TranslateMessage will convert the keys that can be displayed in the WM_KEYDOWN message into WM_CHAR messages

2 Message Parameters

WPARAM-Virtual Key code

LPARAM-related key information

3 Use of messages

3.1 When there is a key message, first enter the system message queue and then be retrieved by the program's message loop

3.2 Handling of messages

4 Order of keyboard messages

For the characters that can be displayed: Wm_keydown wm_char wm_keyup

For non-display characters: Wm_keydown wm_keyup

For system keys: Wm_syskeydown Wm_keyup

If the key has not been released, it will repeat

Wm_keydown (Wm_keychar)