SPE - Cannot index into a null array

Question

I am trying to pass an Item to a SPE Function as follows:

function ImportTask ($importTask, $taskItem) {

    $taskName = $taskItem.Name

    $importTask.ItemTitle = $taskItem.Fields["Item Title"].Value

}

$taskObj = New-Object MyNamespace.Task

$contextItem = Get-Item -Path "."

ImportTask($taskObj, $contextItem)

However, when executed, I get the following error:

Cannot index into a null array.
At line:5 char:2
+     $importTask.ItemTitle = $taskItem.Fields["Item Title"].Value
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : NullArray

Any suggestions why I cannot retrieve the value?

Answer 1

To distinguish positional parameters, Powershell uses spaces instead of commas. By changing your invocation to this, you will fix your problem:

ImportTask $taskObj $contextItem

By using a comma, you are sending an array into the first parameter, and not defining the second.

There are a couple of blog posts by Michael Sorens which detail this in great length:

• https://www.simple-talk.com/dotnet/.net-tools/down-the-rabbit-hole--a-study-in-powershell-pipelines,-functions,-and-parameters/
• https://www.simple-talk.com/sysadmin/powershell/a-plethora-of-powershell-pitfalls/