WPF处理Windows消息

WPF中处理消息首先要获取窗口句柄，创建HwndSource对象 通过HwndSource对象添加消息处理回调函数.

HwndSource类: 实现其自己的窗口过程。 创建窗口之后使用 AddHook 和 RemoveHook 来添加和移除挂钩，接收所有窗口消息。

 private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            HwndSource hwndSource = PresentationSource.FromVisual(this) as HwndSource;//窗口过程
            if (hwndSource != null)
                hwndSource.AddHook(new HwndSourceHook(WndProc));//挂钩
            
        }

HwndSourceHook 类：委托，处理 Win32 窗口消息的方法。

实例：监测U盘的插入和拔出。

public const int WM_DEVICECHANGE = 0x219;
public const int DBT_DEVICEARRIVAL = 0x8000;
public const int DBT_DEVICEREMOVECOMPLETE = 0x8004;

private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
        {
           
            if (msg == WM_DEVICECHANGE)
            {
                switch (wParam.ToInt32())
                {
                   
                    case DBT_DEVICEARRIVAL://U盘插入  
                        m_selBox.Items.Clear();
                        InitCombox();                     
                        break;
                                                                                              
                    case DBT_DEVICEREMOVECOMPLETE: //U盘卸载
                        m_selBox.Items.Clear();
                        InitCombox();                        
                        break;
                                                                                             
                    default:
                        break;
                }
            }          
            return IntPtr.Zero;
        }