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);
        }
       
    }
   
}