我有一个应用程序,我正在寻找一个文本文件,如果对文件做了任何更改,我使用OnChanged事件处理程序来处理事件。我正在使用NotifyFilters。LastWriteTime,但是事件仍然被触发两次。这是代码。
public void Initialize()
{
FileSystemWatcher _fileWatcher = new FileSystemWatcher();
_fileWatcher.Path = "C:\\Folder";
_fileWatcher.NotifyFilter = NotifyFilters.LastWrite;
_fileWatcher.Filter = "Version.txt";
_fileWatcher.Changed += new FileSystemEventHandler(OnChanged);
_fileWatcher.EnableRaisingEvents = true;
}
private void OnChanged(object source, FileSystemEventArgs e)
{
.......
}
在我的情况下,OnChanged被调用两次,当我改变文本文件version.txt并保存它。
很抱歉挖了坟墓,但我已经与这个问题斗争了一段时间,终于想出了一种方法来处理这些多重发射事件。我想要感谢这篇文章中的每一个人,因为我在与这个问题作斗争时已经在许多参考文献中使用了它。
这是我的完整代码。它使用字典来跟踪文件最后一次写入的日期和时间。它比较该值,如果值相同,则抑制事件。然后在启动新线程后设置该值。
using System.Threading; // used for backgroundworker
using System.Diagnostics; // used for file information
private static IDictionary<string, string> fileModifiedTable = new Dictionary<string, string>(); // used to keep track of our changed events
private void fswFileWatch_Changed( object sender, FileSystemEventArgs e )
{
try
{
//check if we already have this value in our dictionary.
if ( fileModifiedTable.TryGetValue( e.FullPath, out sEmpty ) )
{
//compare timestamps
if ( fileModifiedTable[ e.FullPath ] != File.GetLastWriteTime( e.FullPath ).ToString() )
{
//lock the table
lock ( fileModifiedTable )
{
//make sure our file is still valid
if ( File.Exists( e.FullPath ) )
{
// create a new background worker to do our task while the main thread stays awake. Also give it do work and work completed handlers
BackgroundWorker newThreadWork = new BackgroundWorker();
newThreadWork.DoWork += new DoWorkEventHandler( bgwNewThread_DoWork );
newThreadWork.RunWorkerCompleted += new RunWorkerCompletedEventHandler( bgwNewThread_RunWorkerCompleted );
// capture the path
string eventFilePath = e.FullPath;
List<object> arguments = new List<object>();
// add arguments to pass to the background worker
arguments.Add( eventFilePath );
arguments.Add( newEvent.File_Modified );
// start the new thread with the arguments
newThreadWork.RunWorkerAsync( arguments );
fileModifiedTable[ e.FullPath ] = File.GetLastWriteTime( e.FullPath ).ToString(); //update the modified table with the new timestamp of the file.
FILE_MODIFIED_FLAG.WaitOne(); // wait for the modified thread to complete before firing the next thread in the event multiple threads are being worked on.
}
}
}
}
}
catch ( IOException IOExcept )
{
//catch any errors
postError( IOExcept, "fswFileWatch_Changed" );
}
}