Powershell IO.FileSystemWatcher filters

Question

I have created a IO.filesystemwatcher to monitor a folder and take an action when certain file types are written to the location. I am looking for file types .jpg and .tmp. I have named the filter as a variable, and the filter works when including one file type, but not two types.

Code below functions correctly:

$filter = '*.jpg'
New-Object IO.FileSystemWatcher $Folder, $filter -Property @{IncludeSubdirectories = $true;NotifyFilter = [IO.NotifyFilters]'FileName, LastWrite'}

Code below functions correctly:

$filter = '*.tmp'
New-Object IO.FileSystemWatcher $Folder, $filter -Property @{IncludeSubdirectories = $true;NotifyFilter = [IO.NotifyFilters]'FileName, LastWrite'}

Code below DOES NOT function:

$filter = '*.tmp','*jpg'
New-Object IO.FileSystemWatcher $Folder, $filter -Property @{IncludeSubdirectories = $true;NotifyFilter = [IO.NotifyFilters]'FileName, LastWrite'}

I have also tried $filter = '*.tmp' -or '*jpg'

I am sure there's a different way to do this to make it work, but I am not very good at working with IO.filesystemwatcher. Any recommendations are appreciated.

Thanks

Answer 1

The .Filter property is [string]-typed and supports only a single wildcard expressions; from the docs:

Use of multiple filters such as "*.txt|*.doc" is not supported.

It sounds like you'll have to:

• either: watch for changes to all files, by setting .Filter to '' (the empty string), and then perform your own filtering inside your event handler.

• or: set up a separate watcher instance for each filter (wildcard pattern). ^{Thanks, mhhollomon.}