Question

在线请问一个MFC函数..CSNAKEView::OnKeyDown

void CSNAKEView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
switch(nChar)
{……
……}
CView::OnKeyDown(nChar, nRepCnt, nFlags);
}
问题1:参数里的 UINT nRepCnt, UINT nFlags什么意思?
问题2:Switch语句后面的 CView::OnKeyDown(nChar, nRepCnt, nFlags);是什么意思??

Answer 1

参数一：UINT nChar,

虚拟键盘码，
#define VK_LBUTTON 0x01
#define VK_RBUTTON 0x02
#define VK_CANCEL 0x03
#define VK_MBUTTON 0x04

#if(_WIN32_WINNT >= 0x0500)
#define VK_XBUTTON1 0x05
#define VK_XBUTTON2 0x06
#endif

#define VK_BACK 0x08
#define VK_TAB 0x09

#define VK_CLEAR 0x0C
#define VK_RETURN 0x0D

#define VK_SHIFT 0x10
#define VK_CONTROL 0x11
#define VK_MENU 0x12
#define VK_PAUSE 0x13
#define VK_CAPITAL 0x14

#define VK_KANA 0x15
#define VK_HANGEUL 0x15
#define VK_HANGUL 0x15
#define VK_JUNJA 0x17
#define VK_FINAL 0x18
#define VK_HANJA 0x19
#define VK_KANJI 0x19

#define VK_ESCAPE 0x1B

#define VK_CONVERT 0x1C
#define VK_NONCONVERT 0x1D
#define VK_ACCEPT 0x1E
#define VK_MODECHANGE 0x1F

#define VK_SPACE 0x20
#define VK_PRIOR 0x21
#define VK_NEXT 0x22
#define VK_END 0x23
#define VK_HOME 0x24
#define VK_LEFT 0x25
#define VK_UP 0x26
#define VK_RIGHT 0x27
#define VK_DOWN 0x28
#define VK_SELECT 0x29
#define VK_PRINT 0x2A
#define VK_EXECUTE 0x2B
#define VK_SNAPSHOT 0x2C
#define VK_INSERT 0x2D
#define VK_DELETE 0x2E
#define VK_HELP 0x2F

#define VK_LWIN 0x5B
#define VK_RWIN 0x5C
#define VK_APPS 0x5D

#define VK_SLEEP 0x5F

#define VK_NUMPAD0 0x60
#define VK_NUMPAD1 0x61
#define VK_NUMPAD2 0x62
#define VK_NUMPAD3 0x63
#define VK_NUMPAD4 0x64
#define VK_NUMPAD5 0x65
#define VK_NUMPAD6 0x66
#define VK_NUMPAD7 0x67
#define VK_NUMPAD8 0x68
#define VK_NUMPAD9 0x69
#define VK_MULTIPLY 0x6A
#define VK_ADD 0x6B
#define VK_SEPARATOR 0x6C
#define VK_SUBTRACT 0x6D
#define VK_DECIMAL 0x6E
#define VK_DIVIDE 0x6F
#define VK_F1 0x70
#define VK_F2 0x71
#define VK_F3 0x72
#define VK_F4 0x73
#define VK_F5 0x74
#define VK_F6 0x75
#define VK_F7 0x76
#define VK_F8 0x77
#define VK_F9 0x78
#define VK_F10 0x79
#define VK_F11 0x7A
#define VK_F12 0x7B
#define VK_F13 0x7C
#define VK_F14 0x7D
#define VK_F15 0x7E
#define VK_F16 0x7F
#define VK_F17 0x80
#define VK_F18 0x81
#define VK_F19 0x82
#define VK_F20 0x83
#define VK_F21 0x84
#define VK_F22 0x85
#define VK_F23 0x86
#define VK_F24 0x87

#define VK_NUMLOCK 0x90
#define VK_SCROLL 0x91

#define VK_OEM_NEC_EQUAL 0x92 // '=' key on numpad

#define VK_OEM_FJ_JISHO 0x92 // 'Dictionary' key
#define VK_OEM_FJ_MASSHOU 0x93 // 'Unregister word' key
#define VK_OEM_FJ_TOUROKU 0x94 // 'Register word' key
#define VK_OEM_FJ_LOYA 0x95 // 'Left OYAYUBI' key
#define VK_OEM_FJ_ROYA 0x96 // 'Right OYAYUBI' key

#define VK_LSHIFT 0xA0
#define VK_RSHIFT 0xA1
#define VK_LCONTROL 0xA2
#define VK_RCONTROL 0xA3
#define VK_LMENU 0xA4
#define VK_RMENU 0xA5

#if(_WIN32_WINNT >= 0x0500)
#define VK_BROWSER_BACK 0xA6
#define VK_BROWSER_FORWARD 0xA7
#define VK_BROWSER_REFRESH 0xA8
#define VK_BROWSER_STOP 0xA9
#define VK_BROWSER_SEARCH 0xAA
#define VK_BROWSER_FAVORITES 0xAB
#define VK_BROWSER_HOME 0xAC

#define VK_VOLUME_MUTE 0xAD
#define VK_VOLUME_DOWN 0xAE
#define VK_VOLUME_UP 0xAF
#define VK_MEDIA_NEXT_TRACK 0xB0
#define VK_MEDIA_PREV_TRACK 0xB1
#define VK_MEDIA_STOP 0xB2
#define VK_MEDIA_PLAY_PAUSE 0xB3
#define VK_LAUNCH_MAIL 0xB4
#define VK_LAUNCH_MEDIA_SELECT 0xB5
#define VK_LAUNCH_APP1 0xB6
#define VK_LAUNCH_APP2 0xB7

#endif

#define VK_OEM_1 0xBA // ';:' for US
#define VK_OEM_PLUS 0xBB // '+' any country
#define VK_OEM_COMMA 0xBC // ',' any country
#define VK_OEM_MINUS 0xBD // '-' any country
#define VK_OEM_PERIOD 0xBE // '.' any country
#define VK_OEM_2 0xBF // '/?' for US
#define VK_OEM_3 0xC0 // '`~' for US

#define VK_OEM_4 0xDB // '[{' for US
#define VK_OEM_5 0xDC // '\|' for US
#define VK_OEM_6 0xDD // ']}' for US
#define VK_OEM_7 0xDE // ''"' for US
#define VK_OEM_8 0xDF

#define VK_OEM_AX 0xE1 // 'AX' key on Japanese AX kbd
#define VK_OEM_102 0xE2 // "<>" or "\|" on RT 102-key kbd.
#define VK_ICO_HELP 0xE3 // Help key on ICO
#define VK_ICO_00 0xE4 // 00 key on ICO

#if(WINVER >= 0x0400)
#define VK_PROCESSKEY 0xE5
#endif

#define VK_ICO_CLEAR 0xE6

#if(_WIN32_WINNT >= 0x0500)
#define VK_PACKET 0xE7
#endif

#define VK_OEM_RESET 0xE9
#define VK_OEM_JUMP 0xEA
#define VK_OEM_PA1 0xEB
#define VK_OEM_PA2 0xEC
#define VK_OEM_PA3 0xED
#define VK_OEM_WSCTRL 0xEE
#define VK_OEM_CUSEL 0xEF
#define VK_OEM_ATTN 0xF0
#define VK_OEM_FINISH 0xF1
#define VK_OEM_COPY 0xF2
#define VK_OEM_AUTO 0xF3
#define VK_OEM_ENLW 0xF4
#define VK_OEM_BACKTAB 0xF5

#define VK_ATTN 0xF6
#define VK_CRSEL 0xF7
#define VK_EXSEL 0xF8
#define VK_EREOF 0xF9
#define VK_PLAY 0xFA
#define VK_ZOOM 0xFB
#define VK_NONAME 0xFC
#define VK_PA1 0xFD
#define VK_OEM_CLEAR 0xFE

参数二：UINT nRepCnt,

nRepCnt参数保存了键被重击的次数。

参数三：UINT nFlags，值是一个16位的UINT型.各位代表的意义如下:
第0-7位:扫描码
第8位:扩展键,比如说功能键(F1-12),或者数字区的键
第9-10位:没有使用
第11-12位:供Windows内部使用
第13位:状态描述码(如果键按下时ATL键也是按下的,那么值为1,否则为0)
第14位:前一个键的状态(如果是按下的,值为1,否则为0)
第15位:变换状态(如果键是正在被按下,值为1,如果是正在放开,值为0)

2:是让你不关心而且没有处理的键送给 CSNAKEView的父类函数去处理。

Answer 2

首先，MSDN给出了解释 http://msdn.microsoft.com/zh-cn/library/983st27a(v=VS.80).aspx
1.nRepCnt 按键的次数，nFlags一个标志，表示各种按键状态（值的对应定义见链接中的表）
2.调用基类OnKeyDown方法

追问

2.调用基类OnKeyDown方法
是什么意思?能给我详细讲解下吗麻烦...