如何读取文件并配置streamReader对象？

本文介绍了如何读取文件并配置streamReader对象？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在编写程序，在文件更新时从csv文件中读取数据。现在我得到了简单的错误，即这个OnChanged事件在文件更新完成一次时触发两次.bellow是我的代码。

I am writing program which reads data from csv file when file update. Now i got simple error i.e this "OnChanged" event fires two times as file update done one time.bellow is my code.

public void GetData() { try { //for (int i = 0; i >= 0; i++) //{ FileSystemWatcher watcher = new FileSystemWatcher(); watcher.Path = filepath; watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName; // Only watch text files. watcher.Filter = "*.csv"; watcher.Changed += new FileSystemEventHandler(OnChanged); watcher.EnableRaisingEvents = true; //} } catch { } } private void OnChanged(object source, FileSystemEventArgs e) { try { NetworkStream networkStream = clientSocket.GetStream(); line = new string[] { }; using(FileStream fs = new FileStream(e.FullPath,FileMode.Open,FileAccess.Read)) using (StreamReader sr = new StreamReader(e.FullPath)) { String [] line = sr.ReadLine().Split(','); for (int p = 0; p < line.Length; p++) { b = Encoding.ASCII.GetBytes(line[p]); networkStream.Write(b, 0, b.Length); } sr.Close(); sr.Dispose(); fs.Flush(); } } catch { } }

推荐答案

据我所知，没有办法避免文件系统观察者触发多个事件，所以我已经使用解决方法来解决这个问题。 您可以尝试这样的事情。如果您对多个文件进行了大量更新，那么这并非万无一失。在这种情况下，您可能必须使用列表。 As far as I know there is no way to avoid the file system watcher from firing multiple events, so I have used work-around to solve this issue. You can try something like this. It is not foolproof if you have a lot of updates to multiple files. In that case you might have to use a list. private object lockObject = new object(); private string fileNameInUse = ""; private void OnChanged(object source, FileSystemEventArgs e) { // Blocks the second call from being executed lock (lockObject) { if (fileNameInUse == e.FullPath) // This indicates that the file has already been handled. { fileNameInUse = ""; return; } fileNameInUse = e.FullPath; try { NetworkStream networkStream = clientSocket.GetStream(); line = new string[] { }; using(FileStream fs = new FileStream(e.FullPath,FileMode.Open,FileAccess.Read)) using (StreamReader sr = new StreamReader(e.FullPath)) { String [] line = sr.ReadLine().Split(','); for (int p = 0; p < line.Length; p++) { b = Encoding.ASCII.GetBytes(line[p]); networkStream.Write(b, 0, b.Length); } sr.Close(); sr.Dispose(); fs.Flush(); } } catch { } } }

我希望我错了，有更好的解决方案。 [更新] An替代解决方案

I hope I am wrong and there is a better solution. [UPDATE] An alternative solution

private object lockObject = new object(); private void OnChanged(object source, FileSystemEventArgs e) { // Temporary turn off raising new events watcher.EnableRaisingEvents = false; // Blocks the second call from being executed lock (lockObject) { try { NetworkStream networkStream = clientSocket.GetStream(); line = new string[] { }; using(FileStream fs = new FileStream(e.FullPath,FileMode.Open,FileAccess.Read)) using (StreamReader sr = new StreamReader(e.FullPath)) { String [] line = sr.ReadLine().Split(','); for (int p = 0; p < line.Length; p++) { b = Encoding.ASCII.GetBytes(line[p]); networkStream.Write(b, 0, b.Length); } sr.Close(); sr.Dispose(); fs.Flush(); } } catch (Exception ex) // It is always a bad idea to hide exceptions { MessageBox.Show(ex.ToString()); } finally { // Restore raising events watcher.EnableRaisingEvents = true; } } }