Question

Powershell新手。我正在编写一个脚本来监视目录中的文件并将更改报告给控制台。

我注意到我在FS＆＃34;观察者＆＃34;中使用的脚本块中有相当多的代码重复。

这是一个脚本块的片段。如果需要的话，我可以发布整个剧本，它会再延长一段时间，而且还会继续发布。

# Filter all files
$filter = "*.*"
$watcher = New-Object IO.FileSystemWatcher $watchdir, $filter -Property @{
    IncludeSubdirectories = $true
    EnableRaisingEvents = $true
}

# File creation
Register-ObjectEvent $watcher Created -SourceIdentifier Created -Action {
    $path = $Event.SourceEventArgs.FullPath
    $name = $Event.SourceEventArgs.Name
    $changeType = $Event.SourceEventArgs.ChangeType
    $timeStamp = $Event.TimeGenerated
    $message = "The file '$name' was '$changeType' at '$timeStamp'"
    Write-Host $message
}

# File change
Register-ObjectEvent $watcher Changed -SourceIdentifier Changed -Action {
    $path = $Event.SourceEventArgs.FullPath
    $name = $Event.SourceEventArgs.Name
    $changeType = $Event.SourceEventArgs.ChangeType
    $timeStamp = $Event.TimeGenerated
    $message = "The file '$name' was '$changeType' at '$timeStamp'"
    Write-Host $message
}

# File rename
...

# File delete
...

是否有良好的模式或更好的方式来编写它以减少代码量？

Answer 1

在您的示例中，脚本块完全相同，因此在这种情况下，只需将它们放在变量中并传递它：

$action = {
    $path = $Event.SourceEventArgs.FullPath
    $name = $Event.SourceEventArgs.Name
    $changeType = $Event.SourceEventArgs.ChangeType
    $timeStamp = $Event.TimeGenerated
    $console_message = "The file '$name' was '$changeType' at '$timeStamp'"
    Write-Host message
}

# File creation
Register-ObjectEvent $watcher Created -SourceIdentifier Created -Action $action

# File change
Register-ObjectEvent $watcher Changed -SourceIdentifier Changed -Action $action

如果您发布一个示例，其中脚本块中存在冗余，但它们不完全相同，那么将更容易显示如何最好地抽象它的示例。可能没有一个通用的解决方案。

Answer 2

您应该将重用的代码包装到函数中，请参阅此处以获取有关如何执行此操作的说明：http://windowsitpro.com/windows/create-your-own-powershell-functions

在你的情况下，我会创建以下函数：

function FileChange {
  Register-ObjectEvent $watcher Created -SourceIdentifier Created -Action {
  $path = $Event.SourceEventArgs.FullPath
  $name = $Event.SourceEventArgs.Name
  $changeType = $Event.SourceEventArgs.ChangeType
  $timeStamp = $Event.TimeGenerated
  $console_message = "The file '$name' was '$changeType' at '$timeStamp'"
  Write-Host message
}

然后用它来代替重复的代码：

# Filter all files
$filter = "*.*"
$watcher = New-Object IO.FileSystemWatcher $watchdir, $filter -Property @{
IncludeSubdirectories = $true
EnableRaisingEvents = $true
}

# File creation
FileChange()

# File change
FileChange()

如何在脚本块中重复删除代码？

2 个答案: