文件系统观察者和大文件 [英] Filesystem watcher and large files

问题描述

var fsw = new FileSystemWatcher(sPath, "*.PPF");
fsw.NotifyFilter = NotifyFilters.FileName;
fsw.IncludeSubdirectories = true;
fsw.Created += FswCreated;
fsw.EnableRaisingEvents = true;

static void FswCreated(object sender, FileSystemEventArgs e)
{
  string sFile = e.FullPath;
  string[] arrLines = File.ReadAllLines(sFile);
}

这对于大文件会失败，因为该过程没有完成写入文件.该文件是通过网络复制的，所以我不知道文件的大小.需要什么样的同步才能使其稳健?

this fails with large files, because the process is not finnished with writing the file. The file is copied via the Network, so i dont know the size of the file. What kind of syncronisation is required to make this robust?

推荐答案

在 stackoverflow 上找到的解决方案，稍微修改了一下.

Solution found on stackoverflow and modified it a bit.

static bool IsFileLocked(FileInfo file)
{
    FileStream stream = null;

    try
    {
        stream = file.Open(FileMode.Open, 
                 FileAccess.ReadWrite, FileShare.None);
    }
    catch (IOException)
    {
        //the file is unavailable because it is:
        //still being written to
        //or being processed by another thread
        //or does not exist (has already been processed)
        return true;
    }
    finally
    {
        if (stream != null)
            stream.Close();
    }

    //file is not locked
    return false;
}

static void FswCreated(object sender, FileSystemEventArgs e)
{
    string sFile = e.FullPath;

    Console.WriteLine("processing file : " + sFile);

    // Wait if file is still open
    FileInfo fileInfo = new FileInfo(sFile);
    while(IsFileLocked(fileInfo))
    {
        Thread.Sleep(500);
    }

    string[] arrLines = File.ReadAllLines(sFile);
}

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