using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace detectUSB
{
    public partial class mainForm : Form
    {
        private IntPtr m_hNotifyDevNode;

        public mainForm()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Guid dongle = new Guid("4D36E978-E325-11CE-BFC1-08002BE10318");  //dongle

            RegisterNotification(dongle);
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            UnregisterNotification();
        }

        private void RegisterNotification(Guid guid)
        {
            Dbt.DEV_BROADCAST_DEVICEINTERFACE devIF = new Dbt.DEV_BROADCAST_DEVICEINTERFACE();
            IntPtr devIFBuffer;

            //设置HID到GUID
            devIF.dbcc_size = Marshal.SizeOf(devIF);
            devIF.dbcc_devicetype = Dbt.DBT_DEVTYP_DEVICEINTERFACE;
            devIF.dbcc_reserved = 0;
            devIF.dbcc_classguid = guid;

            //为Dll调用分配缓冲区
            devIFBuffer = Marshal.AllocHGlobal(devIF.dbcc_size);

            //复制DevIF到缓冲区
            Marshal.StructureToPtr(devIF, devIFBuffer, true);

            //注册设备通知
            m_hNotifyDevNode = Dbt.RegisterDeviceNotification(this.Handle, devIFBuffer, Dbt.DEVICE_NOTIFY_WINDOW_HANDLE);

            //复制buffer到devIF
            Marshal.PtrToStructure(devIFBuffer, devIF);

            //释放buffer
            Marshal.FreeHGlobal(devIFBuffer);
        }

        //反注册notification
        private void UnregisterNotification()
        {
            uint ret = Dbt.UnregisterDeviceNotification(m_hNotifyDevNode);
        }

        //覆写WndProc
        protected override void WndProc(ref Message m)
        {
            // 拦截WM_DEVICECHANGE消息
            if (m.Msg == Dbt.WM_DEVICECHANGE)
            {
                int nEventType = m.WParam.ToInt32();  //获取消息事件类型

                //判断设备连接或者断开
                if (nEventType == Dbt.DBT_DEVICEARRIVAL || nEventType == Dbt.DBT_DEVICEREMOVECOMPLETE)
                {
                    Dbt.DEV_BROADCAST_HDR hdr = new Dbt.DEV_BROADCAST_HDR();

                    //转换 lparam 为 DEV_BROADCAST_HDR 结构
                    Marshal.PtrToStructure(m.LParam, hdr);

                    if (hdr.dbch_devicetype == Dbt.DBT_DEVTYP_DEVICEINTERFACE)
                    {
                        Dbt.DEV_BROADCAST_DEVICEINTERFACE_1 devIF = new Dbt.DEV_BROADCAST_DEVICEINTERFACE_1();

                        //转换 lparam 为 DEV_BROADCAST_DEVICEINTERFACE 结构
                        Marshal.PtrToStructure(m.LParam, devIF);

                        //从广播消息获取设备路径
                        string devicePath = new string(devIF.dbcc_name);

                        //从字符串中删除空终止的数据
                        int pos = devicePath.IndexOf((char)0);
                        if (pos != -1) devicePath = devicePath.Substring(0, pos);

                        if (nEventType == Dbt.DBT_DEVICEREMOVECOMPLETE)  //设备移除
                        {
                            label1.Text = "Device \"" + devicePath + "\" was removed";
                            MessageBox.Show("Device \"" + devicePath + "\" was removed");
                        }
                        else if (nEventType == Dbt.DBT_DEVICEARRIVAL)   //设备插入
                        {
                            label1.Text = "Device \"" + devicePath + "\" arrived";
                            MessageBox.Show("Device \"" + devicePath + "\" arrived");
                        }

                    }
                }
            }
            base.WndProc(ref m);
        }



    }
}