我有一个简单的要求，即将文件从源文件夹移动到目标文件夹。文件大小约为5mb，一次到达三个（每5秒）。
我现有的机制似乎移动文件但是如果目标文件夹几秒钟无法访问，则从源目录处理的文件不会排队但会丢失。
我的问题是如何创建一个包含在源目录中创建的所有文件并将文件移动到目标的队列？我需要使用后台线程吗？
我的观察者代码看起来像这样。
public sealed class Watcher
{
int eventCount = 0;
#region Private Members
/// <summary>
/// File system watcher variable.
/// </summary>
private FileSystemWatcher fsw = null;
/// <summary>
/// Destination path to use.
/// </summary>
private string destination = @"c:\temp\doc2\";
/// <summary>
/// Source path to monitor.
/// </summary>
private string source = @"c:\temp\doc\";
/// <summary>
/// Default filter type is all files.
/// </summary>
private string filter = "*.bmp";
/// <summary>
/// Monitor all sub directories in the source folder.
/// </summary>
private bool includeSubdirectories = true;
/// <summary>
/// Background worker which will Move files.
/// </summary>
private BackgroundWorker bgWorker = null;
/// <summary>
/// Toggle flag to enable copying files and vice versa.
/// </summary>
private bool enableCopyingFiles = false;
/// <summary>
/// File System watcher lock.
/// </summary>
private object fswLock = new object();
private static Watcher watcherInstance;
#endregion
#region Public Properties
public static Watcher WatcherInstance
{
get
{
if (watcherInstance == null)
{
watcherInstance = new Watcher();
}
return watcherInstance;
}
}
public string Source
{
get
{
return source;
}
set
{
source = value;
}
}
public string Destination
{
get
{
return destination;
}
set
{
destination = value;
}
}
public string Filter
{
get
{
return filter;
}
set
{
filter = value;
}
}
public bool MonitorSubDirectories
{
get
{
return includeSubdirectories;
}
set
{
includeSubdirectories = value;
}
}
public bool EnableCopyingFiles
{
get
{
return enableCopyingFiles;
}
set
{
enableCopyingFiles = value;
}
}
public FileSystemWatcher FSW
{
get
{
return fsw;
}
set
{
fsw = value;
}
}
#endregion
#region Construction
/// <summary>
/// Constructor.
/// </summary>
public Watcher()
{
// Intentionally left blank.
}
#endregion
#region Public Methods
/// <summary>
/// Method which will initialise the required
/// file system watcher objects to starting watching.
/// </summary>
public void InitialiseFSW()
{
fsw = new FileSystemWatcher();
bgWorker = new BackgroundWorker();
}
/// <summary>
/// Method which will start watching.
/// </summary>
public void StartWatch()
{
if (fsw != null)
{
fsw.Path = source;
fsw.Filter = filter;
fsw.IncludeSubdirectories = includeSubdirectories;
fsw.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName | NotifyFilters.LastAccess;
// Setup events.
fsw.Created += fsw_Created;
// Important to set the below otherwise no events will be raised.
fsw.EnableRaisingEvents = enableCopyingFiles;
bgWorker.DoWork += bgWorker_DoWork;
}
else
{
Trace.WriteLine("File System Watcher is not initialised. Setting ISS Fault Alarm Bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
}
}
/// <summary>
/// Method to stop watch.
/// </summary>
public void StopWatch()
{
// Stop Watcher.
if (bgWorker != null)
{
bgWorker.DoWork -= bgWorker_DoWork;
}
if (fsw != null)
{
fsw.Created -= fsw_Created;
}
}
#endregion
#region Private Methods
/// <summary>
/// Method which will do the work on the background thread.
/// Currently Move files from source to destination and
/// monitor disk capacity.
/// </summary>
/// <param name="sender">Object Sender</param>
/// <param name="e">Event Arguments</param>
private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
Trace.WriteLine("ZZZZZ..Event Count:" + eventCount.ToString());
// Extract the file names form the arguments.
FileSystemEventArgs fsea = (FileSystemEventArgs)e.Argument;
// Form the correct filename.
// An assumption has been made that there will always be an '&' symbol in the filename.
// An assumption has been made that the batch code will be added before the first '&' symbol.
string newFileName = string.Empty;
//// First character we are looking for has been found.
//// Sanity checks.
//if (CommonActions.ExtDictionary != null)
//{
// // Add the batch Code.
// // newFileName = fnParts[i] + "_" + CommonActions.ExtDictionary["BatchID"] + "_" + "&";
// // Add the batch code before the filename for easy sorting in windows explorer.
// newFileName = CommonActions.ExtDictionary["BatchID"] + "_" + fsea.Name;
//}
//else
//{
// Batch Code not found. So prefix with hardcoded text.
newFileName = "BatchCode" + "_" + fsea.Name;
//newFileName = fsea.Name;
//}
// We should now have the fully formed filename now.
// Move the file to the new location
string destPath = destination + @"\" + newFileName;
var fi = new FileInfo(fsea.FullPath);
// TODO Check if the file exist.
if (File.Exists(Path.Combine(Source, fsea.Name)))
{
// Check if the file is accessiable.
if (IsAccessible(fi, FileMode.Open, FileAccess.Read))
{
if (!File.Exists(destPath))
{
try
{
// Copy the file.
//File.Copy(fsea.FullPath, destPath);
// Move the file.
//File.Move(fsea.FullPath, destPath);
File.Copy(fsea.FullPath, destPath);
File.SetAttributes(destPath, FileAttributes.ReadOnly);
//Stopwatch sWatch = Stopwatch.StartNew();
//TimeSpan fileDropTimeout = new TimeSpan(0, 0, 10);
//bool fileActionSuccess = false;
//do
//{
// // Copy the file.
// //File.Copy(fsea.FullPath, destPath);
// // Move the file.
// //File.Move(fsea.FullPath, destPath);
// File.Copy(fsea.FullPath, destPath);
// File.SetAttributes(destPath, FileAttributes.ReadOnly);
// fileActionSuccess = true;
//} while (sWatch.Elapsed < fileDropTimeout);
//if(!fileActionSuccess)
//{
// Trace.WriteLine("File Move or File Attribute settings failed.");
// throw new Exception();
//}
// Wait before checking for the file exists at destination.
Thread.Sleep(Convert.ToInt32(ConfigurationManager.AppSettings["ExistsAtDestination"]));
// Check if the file has actually been moved to dest.
if (!File.Exists(destPath))
{
// TODO Raise alarms here.
Trace.WriteLine("Failed to Move. File does not exist in destination. Setting ISS Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
// Notify HMI about the error type.
Trace.WriteLine("Failed to Move. File does not exist in destination. Setting ISS File Move Fault Alarm bit");
}
}
catch (Exception ex)
{
// TODO log the exception and Raise alarm?
Trace.WriteLine("Failed to Move or set attributes on file. Setting ISS Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
// Notify HMI about the error type.
Trace.WriteLine("Failed to Move or set attributes on file. Setting ISS File Move Fault Alarm bit");
}
}
else
{
Trace.WriteLine("File Move failed as the file: " + newFileName + " already exists in the destination folder");
}
}
else
{
Trace.WriteLine("File Move failed. File is not accessible");
}
}
}
/// <summary>
/// Event which is raised when a file is created in the folder which is being watched.
/// </summary>
/// <param name="sender">Object sender</param>
/// <param name="e">Event arguments</param>
private void fsw_Created(object sender, FileSystemEventArgs e)
{
lock (fswLock)
{
eventCount++;
// Start the background worker.
// Check whether if the background worker is busy if not continue.
if (!bgWorker.IsBusy)
{
bgWorker.RunWorkerAsync(e);
}
else
{
Trace.WriteLine("An attempt to use background worker for concurrent tasks has been encountered ");
// Worker thread is busy.
int busyCount = 0;
while (busyCount < 4)
{
// Wait for 500ms and try again.
Thread.Sleep(500);
if (!bgWorker.IsBusy)
{
bgWorker.RunWorkerAsync(e);
break;
}
else
{
Trace.WriteLine("An attempt to use background worker for concurrent tasks has been encountered, attempt " + busyCount);
busyCount++;
}
}
}
}
}
/// <summary>
/// Extension method to check if a file is accessible.
/// </summary>
/// <param name="fi">File Info</param>
/// <param name="mode">File Mode</param>
/// <param name="access">File Access</param>
/// <returns>Attempts three times. True if the file is accessible</returns>
private bool IsAccessible(FileInfo fi, FileMode mode, FileAccess access)
{
bool hasAccess = false;
int i = 0;
while (!hasAccess)
{
try
{
using (var fileStream = File.Open(fi.FullName, mode, access))
{
}
hasAccess = true;
i = 1;
break;
}
catch (Exception ex)
{
if (i < 4)
{
// We will swallow the exception, wait and try again.
Thread.Sleep(500);
// Explicitly set hasaccess flag.
hasAccess = false;
i++;
}
else
{
i = 0;
Trace.WriteLine("Failed to Move. File is not accessable. " + ex.ToString());
// Notify HMI
Trace.WriteLine("Failed to Move. File is not accessable.. Setting ISS Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
// Notify HMI about the error type.
Trace.WriteLine("Failed to Move. File is not accessable.. Setting ISS File Move Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFileCopyFault);
// Explicitly set hasaccess flag.
hasAccess = false;
break;
}
}
}
// return hasAccess;
return true;
}
#endregion
}
我将开始观看以下文件
private void CopyFiles(bool enableCopy)
{
if (enableCopy)
{
// Initialise watcher.
Watcher.WatcherInstance.InitialiseFSW();
// Set Source.
Watcher.WatcherInstance.Source = ConfigurationManager.AppSettings["Source"];
// Set Destination.
Watcher.WatcherInstance.Destination = ConfigurationManager.AppSettings["Destination"];
//Trace.WriteLine("FTP Destination is set to:" + Watcher.WatcherInstance.Destination);
// Set Filter
Watcher.WatcherInstance.Filter = "*.bmp";
// Watch subdirectories?
Watcher.WatcherInstance.MonitorSubDirectories = true;
// Enable events.
Watcher.WatcherInstance.EnableCopyingFiles = enableCopy;
// Start Watch.
Watcher.WatcherInstance.StartWatch();
}
else
{
//if (wchr != null && wchr.FSW != null)
//{
// Stop Watcher.
Watcher.WatcherInstance.StopWatch();
// Stop copying files. As the batch is stopped.
Watcher.WatcherInstance.FSW.EnableRaisingEvents = enableCopy;
//}
}
}
答案 0 :(得分：0)
这些是我的发现，最后似乎移动文件而不会遗漏任何文件。
后台工作者不正确使用 为每个文件创建一个任务，然后让它完成它。
更新的观察者类看起来像这样。
public sealed class Watcher
{
int eventCount = 0;
#region Private Members
/// <summary>
/// File system watcher variable.
/// </summary>
private FileSystemWatcher fsw = null;
/// <summary>
/// Destination path to use.
/// </summary>
private string destination = @"c:\temp\doc2\";
/// <summary>
/// Source path to monitor.
/// </summary>
private string source = @"c:\temp\doc\";
/// <summary>
/// Default filter type is all files.
/// </summary>
private string filter = "*.bmp";
/// <summary>
/// Monitor all sub directories in the source folder.
/// </summary>
private bool includeSubdirectories = true;
/// <summary>
/// Background worker which will Move files.
/// </summary>
private BackgroundWorker bgWorker = null;
/// <summary>
/// Toggle flag to enable copying files and vice versa.
/// </summary>
private bool enableCopyingFiles = false;
/// <summary>
/// File System watcher lock.
/// </summary>
private object fswLock = new object();
private static Watcher watcherInstance;
#endregion
#region Public Properties
public static Watcher WatcherInstance
{
get
{
if (watcherInstance == null)
{
watcherInstance = new Watcher();
}
return watcherInstance;
}
}
public string Source
{
get
{
return source;
}
set
{
source = value;
}
}
public string Destination
{
get
{
return destination;
}
set
{
destination = value;
}
}
public string Filter
{
get
{
return filter;
}
set
{
filter = value;
}
}
public bool MonitorSubDirectories
{
get
{
return includeSubdirectories;
}
set
{
includeSubdirectories = value;
}
}
public bool EnableCopyingFiles
{
get
{
return enableCopyingFiles;
}
set
{
enableCopyingFiles = value;
}
}
public FileSystemWatcher FSW
{
get
{
return fsw;
}
set
{
fsw = value;
}
}
#endregion
#region Construction
/// <summary>
/// Constructor.
/// </summary>
public Watcher()
{
// Intentionally left blank.
}
#endregion
#region Public Methods
/// <summary>
/// Method which will initialise the required
/// file system watcher objects to starting watching.
/// </summary>
public void InitialiseFSW()
{
fsw = new FileSystemWatcher();
bgWorker = new BackgroundWorker();
}
/// <summary>
/// Method which will start watching.
/// </summary>
public void StartWatch()
{
if (fsw != null)
{
fsw.Path = source;
fsw.Filter = filter;
fsw.IncludeSubdirectories = includeSubdirectories;
fsw.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName | NotifyFilters.LastAccess;
// Setup events.
fsw.Created += fsw_Created;
// Important to set the below otherwise no events will be raised.
fsw.EnableRaisingEvents = enableCopyingFiles;
bgWorker.DoWork += bgWorker_DoWork;
}
else
{
Trace.WriteLine("File System Watcher is not initialised. Setting ISS Fault Alarm Bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
}
}
/// <summary>
/// Method to stop watch.
/// </summary>
public void StopWatch()
{
// Stop Watcher.
if (bgWorker != null)
{
bgWorker.DoWork -= bgWorker_DoWork;
}
if (fsw != null)
{
fsw.Created -= fsw_Created;
}
}
#endregion
#region Private Methods
/// <summary>
/// Method which will do the work on the background thread.
/// Currently Move files from source to destination and
/// monitor disk capacity.
/// </summary>
/// <param name="sender">Object Sender</param>
/// <param name="e">Event Arguments</param>
private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
}
private void PerformFileActions(string sourcePath)
{
string extractedFileName = Path.GetFileName(sourcePath);
string newFileName = string.Empty;
newFileName = "BatchCode" + "_" + extractedFileName;
// We should now have the fully formed filename now.
// Move the file to the new location
string destPath = destination + @"\" + newFileName;
var fi = new FileInfo(sourcePath);
// TODO Check if the file exist.
if (File.Exists(Path.Combine(Source, extractedFileName)))
{
// Check if the file is accessiable.
if (IsAccessible(fi, FileMode.Open, FileAccess.Read))
{
if (!File.Exists(destPath))
{
try
{
File.Copy(sourcePath, destPath);
File.SetAttributes(destPath, FileAttributes.ReadOnly);
// Wait before checking for the file exists at destination.
Thread.Sleep(Convert.ToInt32(ConfigurationManager.AppSettings["ExistsAtDestination"]));
// Check if the file has actually been moved to dest.
if (!File.Exists(destPath))
{
// TODO Raise alarms here.
Trace.WriteLine("Failed to Move. File does not exist in destination. Setting ISS Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
// Notify HMI about the error type.
Trace.WriteLine("Failed to Move. File does not exist in destination. Setting ISS File Move Fault Alarm bit");
}
}
catch (Exception ex)
{
// TODO log the exception and Raise alarm?
Trace.WriteLine("Failed to Move or set attributes on file. Setting ISS Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
// Notify HMI about the error type.
Trace.WriteLine("Failed to Move or set attributes on file. Setting ISS File Move Fault Alarm bit");
}
}
else
{
Trace.WriteLine("File Move failed as the file: " + newFileName + " already exists in the destination folder");
}
}
else
{
Trace.WriteLine("File Move failed. File is not accessible");
}
}
}
/// <summary>
/// Event which is raised when a file is created in the folder which is being watched.
/// </summary>
/// <param name="sender">Object sender</param>
/// <param name="e">Event arguments</param>
private void fsw_Created(object sender, FileSystemEventArgs e)
{
lock (fswLock)
{
DateTime lastRead = DateTime.MinValue;
DateTime lastWriteTime = File.GetCreationTime(e.FullPath);
if (lastWriteTime != lastRead)
{
eventCount++;
// Start a new task and forget.
Task.Factory.StartNew(() => {
PerformFileActions(e.FullPath);
});
lastRead = lastWriteTime;
}
}
}
/// <summary>
/// Extension method to check if a file is accessible.
/// </summary>
/// <param name="fi">File Info</param>
/// <param name="mode">File Mode</param>
/// <param name="access">File Access</param>
/// <returns>Attempts three times. True if the file is accessible</returns>
private bool IsAccessible(FileInfo fi, FileMode mode, FileAccess access)
{
bool hasAccess = false;
int i = 0;
while (!hasAccess)
{
try
{
using (var fileStream = File.Open(fi.FullName, mode, access))
{
}
hasAccess = true;
i = 1;
break;
}
catch (Exception ex)
{
if (i < 4)
{
// We will swallow the exception, wait and try again.
Thread.Sleep(500);
// Explicitly set hasaccess flag.
hasAccess = false;
i++;
}
else
{
i = 0;
Trace.WriteLine("Failed to Move. File is not accessable. " + ex.ToString());
// Notify HMI
Trace.WriteLine("Failed to Move. File is not accessable.. Setting ISS Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFault);
// Notify HMI about the error type.
Trace.WriteLine("Failed to Move. File is not accessable.. Setting ISS File Move Fault Alarm bit");
//CommonActions.SetAlarmBit(ApplicationConstants.tag_AlarmTag, ApplicationConstants.bit_ISSFileCopyFault);
// Explicitly set hasaccess flag.
hasAccess = false;
break;
}
}
}
// return hasAccess;
return true;
}
#endregion
}