Empty id results in dynamic drop down causes object reference error
Problem
If a drop down with dynamics bind search results contains empty/null values in the ID column, client web service will throw an error
Solution
Make sure you filter out empty results with the Where-Object cmdlet before using the Select-Object cmdlet
Example:
$computers | where-object { $_.ObjectGUID -ne $null } | select-object @{Name="Id";Expression={[guid]$_.ObjectGUID}}, @{Name="";Expression={ ... }}