U盘加载，卸载，拔出，插入，WM_DEVICECHANGE，WndProc，DBT_DEVICEARRIVAL，DBT_DEVICEREMOVECOMPLETE

最近在做一个和U盘有关的项目，有一个需求是要求显示插入的U盘的盘符，当然了，如果拔出U盘，也应该更新显示，就是显示U口上插入的全部移动设备的全部盘符。

其实就是重写

protected override void WndProc(ref Message m)

方法，根据得到的系统消息来处理，但是如果要实时更新的话，最好加上定时查询U口设备，将查询结果更新，时间的间隔可以自己定义，根据项目情况吧。
下面是完整的代码，如果大家有什么好的建议，欢迎大家一起交流。

using  System;
using  System.Collections.Generic;
using  System.ComponentModel;
using  System.Data;
using  System.Drawing;
using  System.Text;
using  System.IO;
using  System.Windows.Forms;
using  System.Threading;

namespace  WindowsApp
{
    public partial class  ComboBoxForm2 : Form
    {
        private IList<string> diskList = new List<string> ();

        delegate void SetTextCallback(string  s);
        delegate void  ClearListBoxItem();

        private Thread thread = null ;
        private  BackgroundWorker backgroundworker;

        public  ComboBoxForm2()
        {
            InitializeComponent();
        }

        protected override void WndProc(ref  Message m)
        {
            object ojb = new object ();
            try
            {
                 //WM_DEVICECHANGE，系统硬件改变发出的系统消息
                if (m.Msg ==  WndProMsgConst.WM_DEVICECHANGE)
                {
                    switch  (m.WParam.ToInt32())
                    {
                        case  WndProMsgConst.WM_DEVICECHANGE:
                            break ;
                        //DBT_DEVICEARRIVAL，设备检测结束，并且可以使用
                        case  WndProMsgConst.DBT_DEVICEARRIVAL:
                            scanUDisk();
                            listBox1.Items.Clear();
                           foreach (string s in  diskList)
            {
                listBox1.Items.Add(s);
            }
                            break ;
                        //DBT_DEVICEREMOVECOMPLETE,设备卸载或者拔出
                        case  WndProMsgConst.DBT_DEVICEREMOVECOMPLETE:
                            scanUDisk();
                            listBox1.Items.Clear();
                            foreach (string s in  diskList)
                            {
                                listBox1.Items.Add(s);
                            }
                            break ;
                       
                    }
                }
            }
            catch  (Exception ex)
            {
                MessageBox.Show("当前盘不能正确识别，请重新尝试！", "提示" , MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            base.WndProc(ref  m);
        }
        private void button1_Click(object  sender, EventArgs e)
        {
            IList<string> diskList = new List<string> ();
            diskList.Add("k001" );
            diskList.Add("k002" );
            diskList.Add("k003" );
            diskList.Add("k004" );
            comboBox1.DataSource =  diskList;
        }
        /// <summary>
         ///  扫描U口设备
        /// </summary>
         /// <param name="obj"></param>
        private void  scanUDisk()
        {
            diskList.Clear();
            DriveInfo[] drives =  DriveInfo.GetDrives();

            foreach (DriveInfo drive in  drives)
            {
                if ((drive.DriveType == DriveType.Removable) && !drive.Name.Substring(0, 1).Equals("A" ))
                {
                    try
                    {
                        diskList.Add(drive.Name);
                    }
                     catch
                    {
                        MessageBox.Show( "当前盘不能正确识别，请重新尝试！", "提示" , MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }

                }
            }
        }
        private void ComboBoxForm2_Load(object  sender, EventArgs e)
        {
            System.Timers.Timer timer = new System.Timers.Timer(1000 );
            timer.Enabled = true ;
            timer.Elapsed += new  System.Timers.ElapsedEventHandler(fi);
            timer.AutoReset = true ;

            
        }
       
        private void  ThreadProcSafe()
        {

            scanUDisk();
            //MessageBox.Show(diskList.Count.ToString());

             foreach (string s in  diskList)
            {
                SetText(s);
            }
        }
        public void SetText(string  text)
        {
            if (this .listBox1.InvokeRequired)
            {
                if  (listBox1.Items.Contains(text))
                    return ;
                SetTextCallback d = new  SetTextCallback(SetText);
                this.Invoke(d, new object [] { text });
            }
            else
            {
                 if  (listBox1.Items.Contains(text))
                    return ;
                this .listBox1.Items.Add(text);
            }
        }
        void fi(object  sender, System.Timers.ElapsedEventArgs e)
        {
            scanUDisk();
            //listBox1.Items.Clear();
            foreach (string s in  diskList)
            {
                SetText(s);
            }
        }
    }
    /// <summary>
     ///  windows消息的常量
    /// </summary>
    class  WndProMsgConst
    {
        #region WndProc常量
         public const int WM_DEVICECHANGE = 0x219 ;
        public const int DBT_DEVICEARRIVAL = 0x8000 ;
        public const int DBT_CONFIGCHANGECANCELED = 0x0019 ;
        public const int DBT_CONFIGCHANGED = 0x0018 ;
        public const int DBT_CUSTOMEVENT = 0x8006 ;
        public const int DBT_DEVICEQUERYREMOVE = 0x8001 ;
        public const int DBT_DEVICEQUERYREMOVEFAILED = 0x8002 ;
        public const int DBT_DEVICEREMOVECOMPLETE = 0x8004 ;
        public const int DBT_DEVICEREMOVEPENDING = 0x8003 ;
        public const int DBT_DEVICETYPESPECIFIC = 0x8005 ;
        public const int DBT_DEVNODES_CHANGED = 0x0007 ;
        public const int DBT_QUERYCHANGECONFIG = 0x0017 ;
        public const int DBT_USERDEFINED = 0xFFFF ;
        #endregion
    }
}


设备的实时性还是差一点，还有啊，像这样的窗体有很多，我不能每个窗体都copy一遍这些代码吧，如何封装起来呢，控件的线程安全也是问题，还需要改进啊，谁有好的意见可以提出来。

msn:[email protected]
mail:[email protected]

简单封装了一下，封装类如下：

using  System;
using  System.Collections.Generic;
using  System.Text;
using  System.Windows.Forms;
using  System.Threading;
using  System.IO;

namespace  WindowsApp
{
    class  Class1
    {
        private IList<string> diskList = new List<string> ();

        delegate void SetTextCallback(string  s);
        delegate void  ClearListBoxItem();
        private  ListBox _listbox;
        private  Form _form;
        private Thread thread = null ;
        //private BackgroundWorker backgroundworker;

         public  Class1()
        {

            System.Timers.Timer timer = new System.Timers.Timer(1000 );
            timer.Enabled = true ;
            timer.Elapsed += new  System.Timers.ElapsedEventHandler(fi);
            timer.AutoReset = true ;
        }
        public void  filldata(Form form, Message m,ListBox listbox)
        {
            _listbox =  listbox;
            _form =  form;
            try
            {
                 //WM_DEVICECHANGE，系统硬件改变发出的系统消息
                if (m.Msg ==  WndProMsgConst.WM_DEVICECHANGE)
                {
                    switch  (m.WParam.ToInt32())
                    {
                        case  WndProMsgConst.WM_DEVICECHANGE:
                            break ;
                        //DBT_DEVICEARRIVAL，设备检测结束，并且可以使用
                        case  WndProMsgConst.DBT_DEVICEARRIVAL:
                            scanUDisk();
                            _listbox.Items.Clear();
                            foreach (string s in  diskList)
                            {
                                _listbox.Items.Add(s);
                            }
                            break ;
                        //DBT_DEVICEREMOVECOMPLETE,设备卸载或者拔出
                        case  WndProMsgConst.DBT_DEVICEREMOVECOMPLETE:
                            scanUDisk();
                            _listbox.Items.Clear();
                            foreach (string s in  diskList)
                            {
                                _listbox.Items.Add(s);
                            }
                            break ;

                    }
                }
            }
            catch  (Exception ex)
            {
                MessageBox.Show("当前盘不能正确识别，请重新尝试！", "提示" , MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
        public void SetText(string  text)
        {
            if (this ._listbox.InvokeRequired)
            {
                if  (_listbox.Items.Contains(text))
                    return ;
                SetTextCallback d = new  SetTextCallback(SetText);
                _form.Invoke(d, new object [] { text });
            }
            else
            {
                 if  (_listbox.Items.Contains(text))
                    return ;
                this ._listbox.Items.Add(text);
            }
        }
        void fi(object  sender, System.Timers.ElapsedEventArgs e)
        {
            scanUDisk();
            //listBox1.Items.Clear();
            foreach (string s in  diskList)
            {
                SetText(s);
            }
        }/// <summary>
         ///  扫描U口设备
        /// </summary>
         /// <param name="obj"></param>
        private void  scanUDisk()
        {
            diskList.Clear();
            DriveInfo[] drives =  DriveInfo.GetDrives();

            foreach (DriveInfo drive in  drives)
            {
                if ((drive.DriveType == DriveType.Removable) && !drive.Name.Substring(0, 1).Equals("A" ))
                {
                    try
                    {
                        diskList.Add(drive.Name);
                    }
                     catch
                    {
                        MessageBox.Show( "当前盘不能正确识别，请重新尝试！", "提示" , MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }

                }
            }
        }
    } /// <summary>
     ///  windows消息的常量
    /// </summary>
    class  WndProMsgConst
    {
        #region WndProc常量
         public const int WM_DEVICECHANGE = 0x219 ;
        public const int DBT_DEVICEARRIVAL = 0x8000 ;
        public const int DBT_CONFIGCHANGECANCELED = 0x0019 ;
        public const int DBT_CONFIGCHANGED = 0x0018 ;
        public const int DBT_CUSTOMEVENT = 0x8006 ;
        public const int DBT_DEVICEQUERYREMOVE = 0x8001 ;
        public const int DBT_DEVICEQUERYREMOVEFAILED = 0x8002 ;
        public const int DBT_DEVICEREMOVECOMPLETE = 0x8004 ;
        public const int DBT_DEVICEREMOVEPENDING = 0x8003 ;
        public const int DBT_DEVICETYPESPECIFIC = 0x8005 ;
        public const int DBT_DEVNODES_CHANGED = 0x0007 ;
        public const int DBT_QUERYCHANGECONFIG = 0x0017 ;
        public const int DBT_USERDEFINED = 0xFFFF ;
        #endregion
    }
}

使用方法如下：

using  System;
using  System.Collections.Generic;
using  System.ComponentModel;
using  System.Data;
using  System.Drawing;
using  System.Text;
using  System.IO;
using  System.Windows.Forms;
using  System.Threading;

namespace  WindowsApp
{
    public partial class  ComboBoxForm2 : Form
    {
        public  ComboBoxForm2()
        {
            InitializeComponent();
        }

        protected override void WndProc(ref  Message m)
        {
            Class1 c=new  Class1();
            c.filldata(this ,m, listBox1);
            
            base.WndProc(ref  m);
        }
       
    }
   
}