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。
以下是我的方法:
// Consider having a List<String> named _changedFiles
private void OnChanged(object source, FileSystemEventArgs e)
{
lock (_changedFiles)
{
if (_changedFiles.Contains(e.FullPath))
{
return;
}
_changedFiles.Add(e.FullPath);
}
// do your stuff
System.Timers.Timer timer = new Timer(1000) { AutoReset = false };
timer.Elapsed += (timerElapsedSender, timerElapsedArgs) =>
{
lock (_changedFiles)
{
_changedFiles.Remove(e.FullPath);
}
};
timer.Start();
}
这是我在一个项目中用来解决这个问题的解决方案,在该项目中,我将文件作为附件发送到邮件中。
它可以很容易地避免两次触发事件,即使是一个较小的定时器间隔,但在我的情况下,1000是可以的,因为我更喜欢错过一些变化,而不是每秒用> 1条消息淹没邮箱。
至少在同时更改多个文件的情况下,它可以正常工作。
Another solution I've thought of would be to replace the list with a dictionary mapping files to their respective MD5, so you wouldn't have to choose an arbitrary interval since you wouldn't have to delete the entry but update its value, and cancel your stuff if it hasn't changed.
It has the downside of having a Dictionary growing in memory as files are monitored and eating more and more memory, but I've read somewhere that the amount of files monitored depends on the FSW's internal buffer, so maybe not that critical.
Dunno how MD5 computing time would affect your code's performances either, careful =\
我可以通过添加一个函数来检查缓冲区数组中的重复项来做到这一点。
然后使用计时器在数组X时间内未被修改后执行该操作:
-每次有东西写入缓冲区时重置计时器
—对tick执行动作
这还捕获了另一种复制类型。如果修改文件夹内的文件,该文件夹也会引发Change事件。
Function is_duplicate(str1 As String) As Boolean
If lb_actions_list.Items.Count = 0 Then
Return False
Else
Dim compStr As String = lb_actions_list.Items(lb_actions_list.Items.Count - 1).ToString
compStr = compStr.Substring(compStr.IndexOf("-") + 1).Trim
If compStr <> str1 AndAlso compStr.parentDir <> str1 & "\" Then
Return False
Else
Return True
End If
End If
End Function
Public Module extentions
<Extension()>
Public Function parentDir(ByVal aString As String) As String
Return aString.Substring(0, CInt(InStrRev(aString, "\", aString.Length - 1)))
End Function
End Module
试试下面的代码:
class WatchPlotDirectory
{
bool let = false;
FileSystemWatcher watcher;
string path = "C:/Users/jamie/OneDrive/Pictures/Screenshots";
public WatchPlotDirectory()
{
watcher = new FileSystemWatcher();
watcher.Path = path;
watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
| NotifyFilters.FileName | NotifyFilters.DirectoryName;
watcher.Filter = "*.*";
watcher.Changed += new FileSystemEventHandler(OnChanged);
watcher.Renamed += new RenamedEventHandler(OnRenamed);
watcher.EnableRaisingEvents = true;
}
void OnChanged(object sender, FileSystemEventArgs e)
{
if (let==false) {
string mgs = string.Format("File {0} | {1}",
e.FullPath, e.ChangeType);
Console.WriteLine("onchange: " + mgs);
let = true;
}
else
{
let = false;
}
}
void OnRenamed(object sender, RenamedEventArgs e)
{
string log = string.Format("{0} | Renamed from {1}",
e.FullPath, e.OldName);
Console.WriteLine("onrenamed: " + log);
}
public void setPath(string path)
{
this.path = path;
}
}