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using System;using System.Collections.Generic;using System.Text;using System.Windows.Forms; // required for Messageusing System.Runtime.InteropServices; // required for Marshalusing System.IO;using Microsoft.Win32.SafeHandles;// DriveDetector - rev. 1, Oct. 31 2007namespace Dolinay{/// <summary>/// Hidden Form which we use to receive Windows messages about flash drives/// </summary>internal class DetectorForm : Form{private Label label1;private DriveDetector mDetector = null;/// <summary>/// Set up the hidden form./// </summary>/// <param name="detector">DriveDetector object which will receive notification about USB drives, see WndProc</param>public DetectorForm(DriveDetector detector){mDetector = detector;this.MinimizeBox = false;this.MaximizeBox = false;this.ShowInTaskbar = false;this.ShowIcon = false;this.FormBorderStyle = FormBorderStyle.None;this.Load += new System.EventHandler(this.Load_Form);this.Activated += new EventHandler(this.Form_Activated);}private void Load_Form(object sender, EventArgs e){// We don't really need this, just to display the label in designer ...InitializeComponent();// Create really small form, invisible anyway.this.Size = new System.Drawing.Size(5, 5);}private void Form_Activated(object sender, EventArgs e){this.Visible = false;}/// <summary>/// This function receives all the windows messages for this window (form)./// We call the DriveDetector from here so that is can pick up the messages about/// drives arrived and removed./// </summary>protected override void WndProc(ref Message m){base.WndProc(ref m);if (mDetector != null){mDetector.WndProc(ref m);}}private void InitializeComponent(){this.label1 = new System.Windows.Forms.Label();this.SuspendLayout();//// label1//this.label1.AutoSize = true;this.label1.Location = new System.Drawing.Point(13, 30);this.label1.Name = "label1";this.label1.Size = new System.Drawing.Size(314, 13);this.label1.TabIndex = 0;this.label1.Text = "This is invisible form. To see DriveDetector code click View Code";//// DetectorForm//this.ClientSize = new System.Drawing.Size(360, 80);this.Controls.Add(this.label1);this.Name = "DetectorForm";this.ResumeLayout(false);this.PerformLayout();}} // class DetectorForm// Delegate for event handler to handle the device eventspublic delegate void DriveDetectorEventHandler(Object sender, DriveDetectorEventArgs e);/// <summary>/// Our class for passing in custom arguments to our event handlers////// </summary>public class DriveDetectorEventArgs : EventArgs{public DriveDetectorEventArgs(){Cancel = false;Drive = "";HookQueryRemove = false;}/// <summary>/// Get/Set the value indicating that the event should be cancelled/// Only in QueryRemove handler./// </summary>public bool Cancel;/// <summary>/// Drive letter for the device which caused this event/// </summary>public string Drive;/// <summary>/// Set to true in your DeviceArrived event handler if you wish to receive the/// QueryRemove event for this drive./// </summary>public bool HookQueryRemove;}/// <summary>/// Detects insertion or removal of removable drives./// Use it in 1 or 2 steps:/// 1) Create instance of this class in your project and add handlers for the/// DeviceArrived, DeviceRemoved and QueryRemove events./// AND (if you do not want drive detector to creaate a hidden form))/// 2) Override WndProc in your form and call DriveDetector's WndProc from there./// If you do not want to do step 2, just use the DriveDetector constructor without arguments and/// it will create its own invisible form to receive messages from Windows./// </summary>class DriveDetector : IDisposable{/// <summary>/// Events signalized to the client app./// Add handlers for these events in your form to be notified of removable device events/// </summary>public event DriveDetectorEventHandler DeviceArrived;public event DriveDetectorEventHandler DeviceRemoved;public event DriveDetectorEventHandler QueryRemove;/// <summary>/// The easiest way to use DriveDetector./// It will create hidden form for processing Windows messages about USB drives/// You do not need to override WndProc in your form./// </summary>public DriveDetector(){DetectorForm frm = new DetectorForm(this);frm.Show(); // will be hidden immediatellyInit(frm, null);}/// <summary>/// Alternate constructor./// Pass in your Form and DriveDetector will not create hidden form./// </summary>/// <param name="control">object which will receive Windows messages./// Pass "this" as this argument from your form class.</param>public DriveDetector(Control control){Init(control, null);}/// <summary>/// Consructs DriveDetector object setting also path to file which should be opened/// when registering for query remove./// </summary>///<param name="control">object which will receive Windows messages./// Pass "this" as this argument from your form class.</param>/// <param name="FileToOpen">Optional. Name of a file on the removable drive which should be opened./// If null, root directory of the drive will be opened. Opening a file is needed for us/// to be able to register for the query remove message. TIP: For files use relative path without drive letter./// e.g. "SomeFolder\file_on_flash.txt"</param>public DriveDetector(Control control, string FileToOpen){Init(control, FileToOpen);}/// <summary>/// init the DriveDetector object/// </summary>/// <param name="intPtr"></param>private void Init(Control control, string fileToOpen){mFileToOpen = fileToOpen;mFileOnFlash = null;mDeviceNotifyHandle = IntPtr.Zero;mRecipientHandle = control.Handle;mDirHandle = IntPtr.Zero; // handle to the root directory of the flash drive which we openmCurrentDrive = "";}/// <summary>/// Gets the value indicating whether the query remove event will be fired./// </summary>public bool IsQueryHooked{get{if (mDeviceNotifyHandle == IntPtr.Zero)return false;elsereturn true;}}/// <summary>/// Gets letter of drive which is currently hooked. Empty string if none./// See also IsQueryHooked./// </summary>public string HookedDrive{get{return mCurrentDrive;}}/// <summary>/// Gets the file stream for file which this class opened on a drive to be notified/// about it's removal./// This will be null unless you specified a file to open (DriveDetector opens root directory of the flash drive)/// </summary>public FileStream OpenedFile{get{return mFileOnFlash;}}/// <summary>/// Hooks specified drive to receive a message when it is being removed./// This can be achieved also by setting e.HookQueryRemove to true in your/// DeviceArrived event handler./// By default DriveDetector will open the root directory of the flash drive to obtain notification handle/// from Windows (to learn when the drive is about to be removed)./// </summary>/// <param name="fileOnDrive">Drive letter or relative path to a file on the drive which should be/// used to get a handle - required for registering to receive query remove messages./// If only drive letter is specified (e.g. "D:\\", root directory of the drive will be opened.</param>/// <returns>true if hooked ok, false otherwise</returns>public bool EnableQueryRemove(string fileOnDrive){if (fileOnDrive == null || fileOnDrive.Length == 0)throw new ArgumentException("Drive path must be supplied to register for Query remove.");if ( fileOnDrive.Length == 2 && fileOnDrive[1] == ':' )fileOnDrive += '\\'; // append "\\" if only drive letter with ":" was passed in.if (mDeviceNotifyHandle != IntPtr.Zero){// Unregister first...RegisterForDeviceChange(false, null);}if (Path.GetFileName(fileOnDrive).Length == 0 ||!File.Exists(fileOnDrive))mFileToOpen = null; // use root directory...elsemFileToOpen = fileOnDrive;RegisterQuery(Path.GetPathRoot(fileOnDrive));if (mDeviceNotifyHandle == IntPtr.Zero)return false; // failed to registerreturn true;}/// <summary>/// Unhooks any currently hooked drive so that the query remove/// message is not generated for it./// </summary>public void DisableQueryRemove(){if (mDeviceNotifyHandle != IntPtr.Zero){RegisterForDeviceChange(false, null);}}/// <summary>/// Unregister and close the file we may have opened on the removable drive./// Garbage collector will call this method./// </summary>public void Dispose(){RegisterForDeviceChange(false, null);}#region WindowProc/// <summary>/// Message handler which must be called from client form./// Processes Windows messages and calls event handlers./// </summary>/// <param name="m"></param>public void WndProc(ref Message m){int devType;char c;if (m.Msg == WM_DEVICECHANGE){// WM_DEVICECHANGE can have several meanings depending on the WParam value...switch (m.WParam.ToInt32()){//// New device has just arrived//case DBT_DEVICEARRIVAL:devType = Marshal.ReadInt32(m.LParam, 4);if (devType == DBT_DEVTYP_VOLUME){DEV_BROADCAST_VOLUME vol;vol = (DEV_BROADCAST_VOLUME)Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_VOLUME));// Get the drive letterc = DriveMaskToLetter(vol.dbcv_unitmask);//// Call the client event handler//// We should create copy of the event before testing it and// calling the delegate - if anyDriveDetectorEventHandler tempDeviceArrived = DeviceArrived;if ( tempDeviceArrived != null ){DriveDetectorEventArgs e = new DriveDetectorEventArgs();e.Drive = c + ":\\";tempDeviceArrived(this, e);// Register for query remove if requestedif (e.HookQueryRemove){// If something is already hooked, unhook it nowif (mDeviceNotifyHandle != IntPtr.Zero){RegisterForDeviceChange(false, null);}RegisterQuery(c + ":\\");}} // if has event handler}break;//// Device is about to be removed// Any application can cancel the removal//case DBT_DEVICEQUERYREMOVE:devType = Marshal.ReadInt32(m.LParam, 4);if (devType == DBT_DEVTYP_HANDLE){// TODO: we could get the handle for which this message is sent// from vol.dbch_handle and compare it against a list of handles for// which we have registered the query remove message (?)//DEV_BROADCAST_HANDLE vol;//vol = (DEV_BROADCAST_HANDLE)// Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_HANDLE));// if ( vol.dbch_handle ....//// Call the event handler in client//DriveDetectorEventHandler tempQuery = QueryRemove;if (tempQuery != null){DriveDetectorEventArgs e = new DriveDetectorEventArgs();e.Drive = mCurrentDrive; // drive which is hookedtempQuery(this, e);// If the client wants to cancel, let Windows knowif (e.Cancel){m.Result = (IntPtr)BROADCAST_QUERY_DENY;}else{// Change 28.10.2007: Unregister the notification, this will// close the handle to file or root directory also.// We have to close it anyway to allow the removal so// even if some other app cancels the removal we would not know about it...RegisterForDeviceChange(false, null); // will also close the mFileOnFlash}}}break;//// Device has been removed//case DBT_DEVICEREMOVECOMPLETE:devType = Marshal.ReadInt32(m.LParam, 4);if (devType == DBT_DEVTYP_VOLUME){devType = Marshal.ReadInt32(m.LParam, 4);if (devType == DBT_DEVTYP_VOLUME){DEV_BROADCAST_VOLUME vol;vol = (DEV_BROADCAST_VOLUME)Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_VOLUME));c = DriveMaskToLetter(vol.dbcv_unitmask);//// Call the client event handler//DriveDetectorEventHandler tempDeviceRemoved = DeviceRemoved;if (tempDeviceRemoved != null){DriveDetectorEventArgs e = new DriveDetectorEventArgs();e.Drive = c + ":\\";tempDeviceRemoved(this, e);}// TODO: we could unregister the notify handle here if we knew it is the// right drive which has been just removed//RegisterForDeviceChange(false, null);}}break;}}}#endregion#region Private Area/// <summary>/// New: 28.10.2007 - handle to root directory of flash drive which is opened/// for device notification/// </summary>private IntPtr mDirHandle = IntPtr.Zero;/// <summary>/// Class which contains also handle to the file opened on the flash drive/// </summary>private FileStream mFileOnFlash = null;/// <summary>/// Name of the file to try to open on the removable drive for query remove registration/// </summary>private string mFileToOpen;/// <summary>/// Handle to file which we keep opened on the drive if query remove message is required by the client/// </summary>private IntPtr mDeviceNotifyHandle;/// <summary>/// Handle of the window which receives messages from Windows. This will be a form./// </summary>private IntPtr mRecipientHandle;/// <summary>/// Drive which is currently hooked for query remove/// </summary>private string mCurrentDrive;// Win32 constantsprivate const int DBT_DEVTYP_DEVICEINTERFACE = 5;private const int DBT_DEVTYP_HANDLE = 6;private const int BROADCAST_QUERY_DENY = 0x424D5144;private const int WM_DEVICECHANGE = 0x0219;private const int DBT_DEVICEARRIVAL = 0x8000; // system detected a new deviceprivate const int DBT_DEVICEQUERYREMOVE = 0x8001; // Preparing to remove (any program can disable the removal)private const int DBT_DEVICEREMOVECOMPLETE = 0x8004; // removedprivate const int DBT_DEVTYP_VOLUME = 0x00000002; // drive type is logical volume/// <summary>/// Registers for receiving the query remove message for a given drive./// We need to open a handle on that drive and register with this handle./// Client can specify this file in mFileToOpen or we will open root directory of the drive/// </summary>/// <param name="drive">drive for which to register. </param>private void RegisterQuery(string drive){bool register = true;if (mFileToOpen == null){// Change 28.10.2007 - Open the root directory if no file specified - leave mFileToOpen null// If client gave us no file, let's pick one on the drive...//mFileToOpen = GetAnyFile(drive);//if (mFileToOpen.Length == 0)// return; // no file found on the flash drive}else{// Make sure the path in mFileToOpen contains valid drive// If there is a drive letter in the path, it may be different from the actual// letter assigned to the drive now. We will cut it off and merge the actual drive// with the rest of the path.if (mFileToOpen.Contains(":")){string tmp = mFileToOpen.Substring(3);string root = Path.GetPathRoot(drive);mFileToOpen = Path.Combine(root, tmp);}elsemFileToOpen = Path.Combine(drive, mFileToOpen);}try{//mFileOnFlash = new FileStream(mFileToOpen, FileMode.Open);// Change 28.10.2007 - Open the root directoryif (mFileToOpen == null) // open root directorymFileOnFlash = null;elsemFileOnFlash = new FileStream(mFileToOpen, FileMode.Open);}catch (Exception){// just do not register if the file could not be openedregister = false;}if (register){//RegisterForDeviceChange(true, mFileOnFlash.SafeFileHandle);//mCurrentDrive = drive;// Change 28.10.2007 - Open the root directoryif (mFileOnFlash == null)RegisterForDeviceChange(drive);else// old versionRegisterForDeviceChange(true, mFileOnFlash.SafeFileHandle);mCurrentDrive = drive;}}/// <summary>/// New version which gets the handle automatically for specified directory/// Only for registering! Unregister with the old version of this function.../// </summary>/// <param name="register"></param>/// <param name="dirPath">e.g. C:\\dir</param>private void RegisterForDeviceChange(string dirPath){IntPtr handle = Native.OpenDirectory(dirPath);if (handle == IntPtr.Zero){mDeviceNotifyHandle = IntPtr.Zero;return;}elsemDirHandle = handle; // save handle for closing it when unregistering// Register for handleDEV_BROADCAST_HANDLE data = new DEV_BROADCAST_HANDLE();data.dbch_devicetype = DBT_DEVTYP_HANDLE;data.dbch_reserved = 0;data.dbch_nameoffset = 0;//data.dbch_data = null;//data.dbch_eventguid = 0;data.dbch_handle = handle;data.dbch_hdevnotify = (IntPtr)0;int size = Marshal.SizeOf(data);data.dbch_size = size;IntPtr buffer = Marshal.AllocHGlobal(size);Marshal.StructureToPtr(data, buffer, true);mDeviceNotifyHandle = Native.RegisterDeviceNotification(mRecipientHandle, buffer, 0);}/// <summary>/// Registers to be notified when the volume is about to be removed/// This is requierd if you want to get the QUERY REMOVE messages/// </summary>/// <param name="register">true to register, false to unregister</param>/// <param name="fileHandle">handle of a file opened on the removable drive</param>private void RegisterForDeviceChange(bool register, SafeFileHandle fileHandle){if (register){// Register for handleDEV_BROADCAST_HANDLE data = new DEV_BROADCAST_HANDLE();data.dbch_devicetype = DBT_DEVTYP_HANDLE;data.dbch_reserved = 0;data.dbch_nameoffset = 0;//data.dbch_data = null;//data.dbch_eventguid = 0;data.dbch_handle = fileHandle.DangerousGetHandle(); //Marshal. fileHandle;data.dbch_hdevnotify = (IntPtr)0;int size = Marshal.SizeOf(data);data.dbch_size = size;IntPtr buffer = Marshal.AllocHGlobal(size);Marshal.StructureToPtr(data, buffer, true);mDeviceNotifyHandle = Native.RegisterDeviceNotification(mRecipientHandle, buffer, 0);}else{// close the directory handleif (mDirHandle != IntPtr.Zero){Native.CloseDirectoryHandle(mDirHandle);// string er = Marshal.GetLastWin32Error().ToString();}// unregisterif (mDeviceNotifyHandle != IntPtr.Zero){Native.UnregisterDeviceNotification(mDeviceNotifyHandle);}mDeviceNotifyHandle = IntPtr.Zero;mDirHandle = IntPtr.Zero;mCurrentDrive = "";if (mFileOnFlash != null){mFileOnFlash.Close();mFileOnFlash = null;}}}/// <summary>/// Gets drive letter from a bit mask where bit 0 = A, bit 1 = B etc./// There can actually be more than one drive in the mask but we/// just use the last one in this case./// </summary>/// <param name="mask"></param>/// <returns></returns>private static char DriveMaskToLetter(int mask){char letter;string drives = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";// 1 = A// 2 = B// 4 = C...int cnt = 0;int pom = mask / 2;while (pom != 0){// while there is any bit set in the mask// shift it to the righ...pom = pom / 2;cnt++;}if (cnt < drives.Length)letter = drives[cnt];elseletter = '?';return letter;}/* 28.10.2007 - no longer needed/// <summary>/// Searches for any file in a given path and returns its full path/// </summary>/// <param name="drive">drive to search</param>/// <returns>path of the file or empty string</returns>private string GetAnyFile(string drive){string file = "";// First try files in the rootstring[] files = Directory.GetFiles(drive);if (files.Length == 0){// if no file in the root, search whole drivefiles = Directory.GetFiles(drive, "*.*", SearchOption.AllDirectories);}if (files.Length > 0)file = files[0]; // get the first file// return empty string if no file foundreturn file;}*/#endregion#region Native Win32 API/// <summary>/// WinAPI functions/// </summary>private class Native{// HDEVNOTIFY RegisterDeviceNotification(HANDLE hRecipient,LPVOID NotificationFilter,DWORD Flags);[DllImport("user32.dll", CharSet = CharSet.Auto)]public static extern IntPtr RegisterDeviceNotification(IntPtr hRecipient, IntPtr NotificationFilter, uint Flags);[DllImport("user32.dll", CharSet = CharSet.Auto)]public static extern uint UnregisterDeviceNotification(IntPtr hHandle);//// CreateFile - MSDNconst uint GENERIC_READ = 0x80000000;const uint OPEN_EXISTING = 3;const uint FILE_SHARE_READ = 0x00000001;const uint FILE_SHARE_WRITE = 0x00000002;const uint FILE_ATTRIBUTE_NORMAL = 128;const uint FILE_FLAG_BACKUP_SEMANTICS = 0x02000000;static readonly IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);// should be "static extern unsafe"[DllImport("kernel32", SetLastError = true)]static extern IntPtr CreateFile(string FileName, // file nameuint DesiredAccess, // access modeuint ShareMode, // share modeuint SecurityAttributes, // Security Attributesuint CreationDisposition, // how to createuint FlagsAndAttributes, // file attributesint hTemplateFile // handle to template file);[DllImport("kernel32", SetLastError = true)]static extern bool CloseHandle(IntPtr hObject // handle to object);/// <summary>/// Opens a directory, returns it's handle or zero./// </summary>/// <param name="dirPath">path to the directory, e.g. "C:\\dir"</param>/// <returns>handle to the directory. Close it with CloseHandle().</returns>static public IntPtr OpenDirectory(string dirPath){// open the existing file for readingIntPtr handle = CreateFile(dirPath,GENERIC_READ,FILE_SHARE_READ | FILE_SHARE_WRITE,0,OPEN_EXISTING,FILE_FLAG_BACKUP_SEMANTICS | FILE_ATTRIBUTE_NORMAL,0);if ( handle == INVALID_HANDLE_VALUE)return IntPtr.Zero;elsereturn handle;}public static bool CloseDirectoryHandle(IntPtr handle){return CloseHandle(handle);}}// Structure with information for RegisterDeviceNotification.[StructLayout(LayoutKind.Sequential)]public struct DEV_BROADCAST_HANDLE{public int dbch_size;public int dbch_devicetype;public int dbch_reserved;public IntPtr dbch_handle;public IntPtr dbch_hdevnotify;public Guid dbch_eventguid;public long dbch_nameoffset;//public byte[] dbch_data[1]; // = new byte[1];public byte dbch_data;public byte dbch_data1;}// Struct for parameters of the WM_DEVICECHANGE message[StructLayout(LayoutKind.Sequential)]public struct DEV_BROADCAST_VOLUME{public int dbcv_size;public int dbcv_devicetype;public int dbcv_reserved;public int dbcv_unitmask;}#endregion}}