Test-IsFileLocked.ps1

Function Test-IsFileLocked {
    [cmdletbinding()]
    Param (
        [parameter(Mandatory, 
            ValueFromPipeline, 
            ValueFromPipelineByPropertyName)]
        [Alias('FullName', 'PSPath')]
        [string[]]$Path
    )
    Process {
        ForEach ($Item in $Path) {
            # Ensure this is a full path
            $Item = Convert-Path $Item
            # Verify that this is a file and not a directory
            If ([System.IO.File]::Exists($Item)) {
                Try {
                    $FileStream = [System.IO.File]::Open($Item, 'Open', 'Write')
                    $FileStream.Close()
                    $FileStream.Dispose()
                    $IsLocked = $False
                    return $False
                }
                Catch [System.UnauthorizedAccessException] {
                    $IsLocked = 'AccessDenied'
                }
                Catch {
                    $IsLocked = $True
                    return $True
                }
                [pscustomobject]@{
                    File     = $Item
                    IsLocked = $IsLocked
                }
            }
        }
    }
}