ProjectOrphants.psm1

function Search-ItemsRecursive{
  [CmdletBinding()]
  param($projectItems, $filter, [switch]$recurse=$false)
  foreach ($item in $projectItems) {
    if($(. $filter $item))
    {
        $item
    }else{
        if(($item.ProjectItems -ne $null) -and $recurse){
            Search-ItemsRecursive -projectItems $item.ProjectItems -filter $filter -recurse:$recurse
        }
    }
  }
}

function Find-OrphantFilesInSolution([switch]$IgnoreObj=$true){
    Get-Project -All | Find-OrphantFilesInProject -IgnoreObj:$IgnoreObj
}    

function Find-OrphantFilesInProject{    
    [CmdletBinding()]
    param([Parameter(ValueFromPipeline=$true)]$Projects, [switch]$IgnoreObj=$true)
    process{
        $toProcess = if($Projects){$Projects}else{Get-Project}    
        foreach($p in $toProcess){
            $projectPath = Split-Path $p.FullName -Parent
            $csFilesInProject = Search-ItemsRecursive -projectItems $p.ProjectItems -filter {param($item)$item.Name -like "*.cs"} -recurse |% {$_.Properties.Item("FullPath").Value}
            dir $projectPath -Filter "*.cs" -Recurse |? { $csFilesInProject -notcontains $_.FullName } |? {(-not $IgnoreObj) -or ($_.Directory -notlike "*\obj*")} |select FullName 
        }
    }    
}
Export-ModuleMember -Function Find-OrphantFilesInSolution, Find-OrphantFilesInProject