`-Filter` is more performant than `-Include`, so if you don't have a lot of different extensions, simply concatenating two filtered lists might be faster.



    $files  = Get-ChildItem -Path "H:\stash\" -Filter *.rdlc -Recurse 
    $files += Get-ChildItem -Path "H:\stash\" -Filter *.rdl  -Recurse 

I compared the output with a timer like this:



    $stopwatch = [System.Diagnostics.Stopwatch]::StartNew()
    # Do Stuff Here
    $stopwatch.Stop()
    Write-Host "$([Math]::Round($stopwatch.Elapsed.TotalSeconds)) seconds ellapsed"

I'm trying to write a PowerShell script to build a list of files, from several directories. After all directories have been added to the main list, I'd like to do the same processing on all files.

This is what I have:

    $items = New-Object Collections.Generic.List[IO.FileInfo]

    $loc1 = @(Get-ChildItem -Path "\\server\C$\Program Files (x86)\Data1\" -Recurse)
    $loc2 = @(Get-ChildItem -Path "\\server\C$\Web\DataStorage\" -Recurse)

    $items.Add($loc1) # This line fails (the next also fails)
    $items.Add($loc2)

    # Processing code is here

which fails with this error:

> Cannot convert argument "0", with
> value: "System.Object[]", for "Add" to
> type "System.IO.FileInfo": "Cannot
> convert the "System.Object[]" va lue
> of type "System.Object[]" to type
> "System.IO.FileInfo"."

I am mostly interested in what is the correct approach for this type of situation. I realize that my code is a very [C][1] way of doing it -- if there is a more PowerShell way to acomplish the same task, I'm all for it. The key, is that the number of `$loc#'s` may change over time, so adding and removing one or two should be easy in the resulting code.

  [1]: http://en.wikipedia.org/wiki/C_%28programming_language%29
