我向在对话框类中添加WM_DEVICECHANGE的处理函数总是出现error link2001,信息如下:
错误 1 error LNK2001: 无法解析的外部符号 "public: int __thiscall CDeviceMonitorDlg::OnDeviceChange(unsigned int,unsigned long)" (?OnDeviceChange@CDeviceMonitorDlg@@QAEHIK@Z)
错误 2 fatal error LNK1120: 1 个无法解析的外部命令代码如下
1.注册消息
BEGIN_MESSAGE_MAP(CDeviceMonitorDlg, CDialog)
ON_WM_SYSCOMMAND()
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
//}}AFX_MSG_MAP
ON_WM_DESTROY()
ON_MESSAGE(WM_SYSTRAY,OnNotifyIcon)
ON_WM_NCPAINT()
ON_WM_DEVICECHANGE()  //注册消息映射
END_MESSAGE_MAP()
2.函数声明
DECLARE_MESSAGE_MAP()
public:
afx_msg void OnDestroy();
afx_msg LRESULT OnNotifyIcon(WPARAM wParam,LPARAM lParam);
afx_msg BOOL OnDeviceChange(UINT nEventType,DWORD_PTR dwData);
3.函数实现
BOOL OnDeviceChange(UINT nEventType,DWORD_PTR dwData)
{
return TRUE;
}