鼠標(biāo)滾輪問題 
相關(guān)的例子:下載>>>  作者：山原依綱 于2008-7-19上傳   

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     前幾天在CSDN上看到一個(gè)VB高手準(zhǔn)備收徒弟，面試的題目是“編寫通過鼠標(biāo)滾輪來(lái)控制窗口大小的程序”。居然很多人認(rèn)為這個(gè)題目很困難。趁著這個(gè)機(jī)會(huì)，我也研究了一下鼠標(biāo)滾輪的問題。

 

當(dāng)鼠標(biāo)滾輪轉(zhuǎn)動(dòng)時(shí)，WM_MOUSEWHEEL消息將會(huì)送至當(dāng)前聚焦的窗口。

 

WM_MOUSEWHEEL Notification

The WM_MOUSEWHEEL message is sent to the focus window when the mouse wheel is rotated. The DefWindowProc function propagates the message to the window's parent. There should be no internal forwarding of the message, since DefWindowProc propagates it up the parent chain until it finds a window that processes it.

A window receives this message through its WindowProc function. 

Syntax

WM_MOUSEWHEEL

    WPARAM wParam

    LPARAM lParam;

    

Parameters

wParam

The high-order word indicates the distance the wheel is rotated, expressed in multiples or divisions of WHEEL_DELTA, which is 120. A positive value indicates that the wheel was rotated forward, away from the user; a negative value indicates that the wheel was rotated backward, toward the user. 

高word表明滾輪轉(zhuǎn)動(dòng)的距離，以WHEEL_DELTA（120）為單位。正數(shù)表明向前轉(zhuǎn)動(dòng)，方向是遠(yuǎn)離使用者。負(fù)數(shù)表示向回轉(zhuǎn)動(dòng)，轉(zhuǎn)向使用者。

The low-order word indicates whether various virtual keys are down. This parameter can be one or more of the following values. 

低word表明此時(shí)是否有虛擬鍵按下。這個(gè)參數(shù)是如下一個(gè)或者多個(gè)值的組合，

MK_CONTROL

The CTRL key is down. 

MK_LBUTTON

The left mouse button is down.

MK_MBUTTON

The middle mouse button is down.

MK_RBUTTON

The right mouse button is down.

MK_SHIFT

The SHIFT key is down.

MK_XBUTTON1

Windows 2000/XP: The first X button is down.

MK_XBUTTON2

Windows 2000/XP: The second X button is down.

lParam

The low-order word specifies the x-coordinate of the pointer, relative to the upper-left corner of the screen. 

低word表明以左上角為原點(diǎn)的當(dāng)前鼠標(biāo)所在的x坐標(biāo)。

The high-order word specifies the y-coordinate of the pointer, relative to the upper-left corner of the screen. 

高word表明以左上角為起點(diǎn)的當(dāng)前鼠標(biāo)所在的y坐標(biāo)。

 

Return Value

If an application processes this message, it should return zero. 

如果應(yīng)用程序處理了這個(gè)消息，應(yīng)該返回0.

看上去應(yīng)用起來(lái)應(yīng)該非常簡(jiǎn)單，于是編寫了簡(jiǎn)單的Demo：

 

;MASMPlus 代碼模板 - 普通的 Windows 程序代碼

 

.386

.Model Flat, StdCall

Option Casemap :None

　

Include windows.inc

Include user32.inc

Include kernel32.inc

Include gdi32.inc

 

includelib gdi32.lib

IncludeLib user32.lib

IncludeLib kernel32.lib

include macro.asm

   

   WinMain PROTO :DWORD,:DWORD,:DWORD,:DWORD

   WndProc PROTO :DWORD,:DWORD,:DWORD,:DWORD

   

.DATA

   szClassName db "MASMPlus_Class",0

   

.DATA?

   hInstance  dd ?

   

.CODE

START:

　

   invoke GetModuleHandle,NULL

   mov hInstance,eax

   invoke WinMain,hInstance,NULL,NULL,SW_SHOWDEFAULT

   invoke ExitProcess,0

　

WinMain proc hInst:DWORD,hPrevInst:DWORD,CmdLine:DWORD,CmdShow:DWORD

   LOCAL wc    :WNDCLASSEX

   LOCAL msg   :MSG

   local hWnd :HWND

   

   mov wc.cbSize,sizeof WNDCLASSEX

   mov wc.style,CS_HREDRAW or CS_VREDRAW or CS_BYTEALIGNWINDOW

   mov wc.lpfnWndProc,offset WndProc

   mov wc.cbClsExtra,NULL

   mov wc.cbWndExtra,NULL

   push hInst

   pop wc.hInstance

   mov wc.hbrBackground,COLOR_BTNFACE+1

   mov wc.lpszMenuName,NULL

   mov wc.lpszClassName,offset szClassName

   invoke LoadIcon,hInst,100

   mov wc.hIcon,eax

   invoke LoadCursor,NULL,IDC_ARROW

   mov wc.hCursor,eax

   mov wc.hIconSm,0

   invoke RegisterClassEx, ADDR wc

   invoke CreateWindowEx,NULL,ADDR szClassName,CTXT("http://www.aogosoft.com"),WS_OVERLAPPEDWINDOW,200,200,400,200,NULL,NULL,hInst,NULL

   mov hWnd,eax

   invoke ShowWindow,hWnd,SW_SHOWNORMAL

   invoke UpdateWindow,hWnd

   

   StartLoop:

       invoke GetMessage,ADDR msg,NULL,0,0

          cmp eax, 0

          je ExitLoop

              invoke TranslateMessage, ADDR msg

              invoke DispatchMessage, ADDR msg

          jmp StartLoop

   ExitLoop:

   

mov eax,msg.wParam

ret

WinMain endp

WndProc proc hWin:DWORD,uMsg:DWORD,wParam :DWORD,lParam :DWORD

   .if uMsg==WM_CREATE

   .elseif uMsg == WM_MOUSEWHEEL   

       mov eax,wParam      ;真正有用的代碼只有紅色一點(diǎn)點(diǎn)

       shr eax,16

       test   eax,8000h

       jz  wheeldown

       invoke SetWindowText,hWin,CTXT("向下滾！")

       jmp @f

     wheeldown:  

       invoke SetWindowText,hWin,CTXT("向上滾！")

     @@:  

   .elseif uMsg == WM_DESTROY

       invoke PostQuitMessage,NULL

   .else

       invoke DefWindowProc,hWin,uMsg,wParam,lParam

   .endif

   ret

WndProc endp

END START

希望本文能起到拋磚引玉的作用，記得鼠標(biāo)除了左右鍵，還有這樣一個(gè)非常方便的功能。

 



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