I am tring to wrtie a function ‘Edit-ContentOrder’ that accepts input from the pipeline via get-childitem. It is expected that the pipeline will provide filesystem objects ie gci on a folder containing .jpgs. Since gci on a directory will return FileInfo objects which contains Name and Directory properties, I thought the correct definition of this function would be as follows:
function Edit-ContentOrder {
[CmdletBinding(SupportsShouldProcess)]
[Alias('Reorder-Contents')]
param(
[Parameter(ValueFromPipelineByPropertyName=$true)]
[string[]]$Name,
[Parameter(ValueFromPipelineByPropertyName=$true)]
[string[]]$Directory
)
begin{}
process {
}
end{}
}
What I have discovered is that this is not quite right. The first thing to address is for each element in the pipeline what actually are $Name and $Directory? As you can see from the definition, they are both defined as arrays of strings. However on each individual iteration I need to address each element 1 at a time. If I print the type of either $Name or $Directory, they show: "string[]". If that is the case, how do I address individual elements? $_ actually refers to the FileInfo which in itelf is the item in the pipeline and and the Name and Directory properies. But if I use $_, then what is the point of defining Name and Directory as pipeline parameters?
I suppose I could perform a loop on $Name, but then I couldnt easily get the corresponding $Directory. See the really strange thing is if I print out $Name and $Directory, they do indeed print out the individual elements as if $Name is an individual string:
Write-Host "*** Reorder-Contents; Type: '$($Name.GetType())', name: '$Name'";
Write-Host "=== Element: $_, Type: $($_.GetType())"
displays multiples of these:
--------------------
*** Reorder-Contents; Type: 'string[]', name: 'log-info_0110.jpg'
=== Element: C:\Users\PLASTIKFAN\dev\app-logs\colour-extractor\log-info_0110.jpg, Type: System.IO.FileInfo
--------------------
As you can see 'log-info_0110.jpg' is an individual string, but its type is still string[]. How is this right? Its odd because sometimes I can address $Name as though its an individual string:
<hr />
[Regex]$expressionObj = New-Object Regex($Expression, $RegexOptionsEnum);
$m = $expressionObj.Match($Name);
<hr />
This works as one would want, ie we're executing a regular expression against $Name (as in individual string)
However, if I try and use Join-Path, using $Directory and $Name, join-path complains because they are defined as string[] and not string:
<hr />
$fullname = Join-Path -Path $Directory -ChildPath $Name;
<hr />
results in:
<hr />
Join-Path: C:\Users\PLASTIKFAN\dev\github\PoSh\UtilsModule\Public\Edit-ContentOrder.ps1:35:55
Line |
35 | $fullname = Join-Path -Path $Directory -ChildPath $Name;
| ~~~~~
| Cannot convert 'System.String[]' to the type 'System.String' required by parameter 'ChildPath'. Specified method is
| not supported.
<hr />