基于win32的USB识别程序

最近遇到客户提出插入我们公司加密锁产品，弹出指定锁内网址页面的需求，其中需要用到usb设别相关程序，对于我这样的VC小白来说，首先只能先搜资料了，废话不多说，直接上demo。

#include <tchar.h>  #include <string>  #include <iostream>  #include <Windows.h>    #include <dbt.h>    /*------------------------------------------------------------------ FirstDriveFromMask( unitmask )  Description Finds the first valid drive letter from a mask of drive letters. The mask must be in the format bit 0 = A, bit 1 = B, bit 2 = C,  and so on. A valid drive letter is defined when the  corresponding bit is set to 1.  Returns the first drive letter that was found. --------------------------------------------------------------------*/  char FirstDriveFromMask(ULONG unitmask)  {      char i;            for (i = 0; i < 26; ++i)      {          if (unitmask & 0x1)              break;          unitmask = unitmask >> 1;      }            return(i + 'A');  }    LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)  {      PDEV_BROADCAST_HDR lpdb = (PDEV_BROADCAST_HDR)lParam;      PDEV_BROADCAST_VOLUME lpdbv = (PDEV_BROADCAST_VOLUME)lpdb;      TCHAR szMsg[80];      char driveName;            switch(uMsg)      {      case WM_DEVICECHANGE:          switch(wParam )          {          case DBT_DEVICEARRIVAL:                  driveName = FirstDriveFromMask(lpdbv->dbcv_unitmask);                  sprintf(szMsg, "USB Drive %c: has inserted.\n", driveName);                  printf("%s\r\n", szMsg);                  MessageBox(hWnd, szMsg, TEXT("WM_DEVICECHANGE"), MB_OK);              break;          case DBT_DEVICEREMOVECOMPLETE:                  driveName = FirstDriveFromMask(lpdbv->dbcv_unitmask);                  sprintf(szMsg, "USB Drive %c: has removed.\n", driveName);                  printf("%s\r\n", szMsg);                  MessageBox(hWnd, szMsg, TEXT("WM_DEVICECHANGE"), MB_OK );              break;          default:              ;          }          break;          default:              ;      }            return DefWindowProc(hWnd, uMsg, wParam, lParam);  }    int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])  {      TCHAR szClassName[] = _T("MyApp");      WNDCLASS wndcls = {0};      wndcls.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);      wndcls.hCursor = (HCURSOR)LoadCursor(NULL, IDC_ARROW);      wndcls.hIcon = (HICON)LoadIcon(NULL, IDI_APPLICATION);      wndcls.lpfnWndProc = WndProc;      wndcls.lpszClassName = szClassName;      if(!RegisterClass(&wndcls))      {          printf("RegisterClass Failed!\r\n");          return 0;      }            HWND hWnd = CreateWindow(szClassName, szClassName, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT,          CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, NULL, NULL);      if(NULL == hWnd)      {          printf("CreateWindow Failed!\r\n");          return 0;      }      ShowWindow(hWnd, SW_HIDE);      UpdateWindow(hWnd);            MSG msg;      while(GetMessage(&msg, NULL, NULL, NULL))      {          TranslateMessage(&msg);          DispatchMessage(&msg);      }      return 0;  }  

可是问题来了，这两个信号：DBT_DEVICEARRIVAL:  DBT_DEVICEREMOVECOMPLETE:  只能分别对应U盘的插入和拔出，针对加密锁却无半点响应。抓耳挠腮不得其解情况下，直接插拔加密锁让它打印：switch(wParam )中的wParam，结果打印的数为0X0007，对应宏为：DBT_DEVNODES_CHANGED，找到对应解释为：/ *
*消息= WM_DEVICECHANGE
*按钮= DBT_DEVNODES_CHANGED
* lParam = 0
*
*发送当configmg结束进程树一批。一些devnodes
*可能被添加或删除。这是被ring3人使用
*需要刷新任何devnode改变(如发生
*设备管理器)。人们应该使用特定于特定设备
* DBT_DEVICE *。

* /

不太懂为何如此，也闹不清普通U盘和我们加密锁的关于USB驱动的实质区别，但是目前问题已经解决，至于原因如何，日后深究，先以此文记之，留作备忘。