创建和关闭文件后如何使 FileSystemWatcher 触发操作？答案

【问题标题】：How to make FileSystemWatcher trigger action after files are created and closed?创建和关闭文件后如何使 FileSystemWatcher 触发操作？
【发布时间】：2014-05-20 21:06:53
【问题描述】：

我使用下面的代码来启动

$folder = '....' 
$filter = '*.csv' 
$fsw = New-Object IO.FileSystemWatcher $folder, $filter -Property @{
    IncludeSubdirectories = $true;
    NotifyFilter = [IO.NotifyFilters]'FileName, LastWrite' }
Register-ObjectEvent $fsw Created -SourceIdentifier FileCreated -Action {
    $name = $Event.SourceEventArgs.Name
    $changeType = $Event.SourceEventArgs.ChangeType
    $timeStamp = $Event.TimeGenerated
    Write-Host "The file '$name' was $changeType at $timeStamp" -fore green
    ... #execute a program to read the files, 
    ... #may fail because file is still being writing..... }

但是，我会在创建文件后立即触发该操作。文件夹中可能有数百个拥抱文件要转储/复制。是否可以测试文件写入是否完成？

【问题讨论】：

标签： c# windows powershell filesystemwatcher

【解决方案1】：

一种可能性：

Try {
  [IO.File]::OpenWrite($File).Close()
  #Do something with file
}
Catch {}

如果文件已完成写入并已关闭，[IO.File]::OpenWrite($File).Close() 将打开文件进行写入，然后立即关闭它。如果仍在写入，则无法获得写入锁，命令将失败，脚本将进入 Catch 块并等待下一个 LastWrite 事件。

【讨论】：