c# - FileSystemWatcher:如何只为目录中的新文件增加事件？

Question

FileSystemWatcher:如何只为目录中的新文件触发事件？

我有一个目录，我的服务扫描它。我使用 FileSystemWatcher:

构造函数:

if(Directory.Exists(_dirPath))
{
    _fileSystemWatcher = new FileSystemWatcher(_dirPath);
}

然后，我订阅目录:

public void Subscribe()
{
    try
    {
        //if (_fileSystemWatcher != null)
        //{
        //    _fileSystemWatcher.Created -= FileSystemWatcher_Created;
        //    _fileSystemWatcher.Dispose();
        //}

        if (Directory.Exists(_dirPath))
        {                    
            _fileSystemWatcher.EnableRaisingEvents = true;
            _fileSystemWatcher.Created += FileSystemWatcher_Created;
            _fileSystemWatcher.Filter = "*.txt";                 
        }                    
}

但是，问题是我想在创建(或复制)新文件时获取事件。相反，我从该目录中已存在的所有文件中获取事件。

如何只从新文件中获取事件？谢谢!

Answer 1

通过将 NotifyFilter 设置为 NotifyFilters.FileName | NotifyFilters.CreationTime | NotifyFilters.LastWrite 您可以查看是否创建了新文件。

您还需要在发生任何更改后检查引发的事件中的 e.ChangeType == WatcherChangeTypes.Created。

static void Main(string[] args)
{
    FileSystemWatcher watcher = new FileSystemWatcher();
    string filePath = @"d:\watchDir";
    watcher.Path = filePath;
    watcher.EnableRaisingEvents = true;

    watcher.NotifyFilter = NotifyFilters.FileName | NotifyFilters.CreationTime | NotifyFilters.LastWrite;

    watcher.Filter = "*.*";
    watcher.IncludeSubdirectories = true;
    watcher.Created += new FileSystemEventHandler(OnFileCreated);

    new System.Threading.AutoResetEvent(false).WaitOne();
}

private static void OnFileCreated(object sender, FileSystemEventArgs e)
{
    if (e.ChangeType == WatcherChangeTypes.Created)
        // some code            
}