Can't use Array with Where-Object on Get-Process

Question

I am writing a script where, amongst other things, it needs to react on process used by a popup window.
This popup window has the name in the MainWindowTitle property of Get-Process.

As a test I create the following array:

$WindowTitleNames = @("notepad","powershell")

I then open Notepad.

When I run the following, without using the array, I get this output:

Get-Process | Where-Object MainWindowTitle -Match "notepad" | select Processname, MainWindowTitle

ProcessName MainWindowTitle

---

Notepad Untitled - Notepad
notepad++ *new 4 - Notepad++

But when I run it with the array it doesn't return anything.
However, when I add "Untitled - Notepad" to the array, it will show the Notepad process.

Get-Process | Where-Object {$_.MainWindowTitle -in $WindowTitleNames} | select Processname, MainWindowTitle

ProcessName MainWindowTitle

---

Notepad Untitled - Notepad

Changing the -in to -match or -like doesn't help here.
It seems that when I want to use an array I have to use exact MainWindowTitle values.
But my problem is that I don't always know which name will popup, so I want to use "notepad", or "powershell" (these are examples).
Then I can create a if statement like this:

if ($WindowTitle.ProcessName -eq 'notepad' -or 'powershell') {
    this-function
    that-function
}

I hope someone can explain why I can't use a array here, and what I can do to make it work like I have in mind.
Of course I have searched and I can find examples, but not in relation to Get-Process and $_.MainWindowTitle or something similar.

Answer 1

You can't use "-match" because that operates on a string object. You can't use "-in" because that uses exact matches, not partial ones.

$WindowTitleNames = @("notepad", "powershell")   # values may be simple strings or regexes
Get-Process "notepad" | 
    ForEach-Object {
        foreach ($title in $WindowTitleNames) {
            if ($_.MainWindowTitle -match $title) {
                Select-Object -InputObject $_ Processname, MainWindowTitle
            }
        }
    }