Powershell Forms Textbox value invalid?

Question

Can you please let me know what is wrong with this code?

$SearchUser.Add_Click(
{
  $Output.text = 
   Get-AdUser -Filter "Surname -like $entry" |
   select name, samaccountname
}
)

I keep getting this error:

Get-aduser : Error parsing query: 'Surname -like rondon' Error Message: 'syntax error' at position: '15'.
At line:50 char:11
+ $search = Get-aduser -Filter "Surname -like $entry" | select name, sa ...
+           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ParserError: (:) [Get-ADUser], ADFilterParsingException
    + FullyQualifiedErrorId : ActiveDirectoryCmdlet:Microsoft.ActiveDirectory.Management.ADFilterParsingExcepti
   on,Microsoft.ActiveDirectory.Management.Commands.GetADUser

Filter works standalone in powershell but not via the form

Answer 1

tl;dr

Your Get-ADUser -Filter argument isn't well-formed; use:

• Either: "Surname -like `"$entry`"" (up-front string interpolation, requires embedded quoting)

  • Note: Only stand-alone variable references can be embedded as-is inside expandable "..." literals; embedding expressions or commands requires enclosure in $(...), the subexpression operator, e.g. "Surname -like `"$($entry.Text)`"" or
    "Surname -like `"$(Get-Entry)`""

• Or: 'Surname -like $entry' (let the AD provider evaluate the variable, do not use embedded quoting)

  • Note: This approach fundamentally only works with stand-alone variable references, not with attempts to access properties (e.g 'Surname -like $entry.Text' or subexpressions (e.g. 'Surname -like $(Get-EntryName)')

  • While the form { Surname -like $entry } is often seen in practice, it is best avoided so as to prevent conceptual confusion - see this answer.

---

As for what you tried:

-Filter "Surname -like $entry"

• Since you're using an expandable (double-quoted) string ("..."), i.e. up-front string interpolation, the value of $entry is placed as-is inside the resulting string value.

• Thus, with $entry containing verbatim rondon, what the -Filter argument receives is verbatim Surname -like rondon, which causes a syntax error, because the RHS of the -like operator must either be a quoted string or a reference to a PowerShell variable.

  • It is important to note that while the -Filter parameter expects expression that are PowerShell-like, they are not PowerShell expressions, and instead interpreted by the Active Directory provider. The expression language supported in a -Filter argument is both much more limited than what PowerShell supports and exhibits subtle yet important differences in behavior. Again, see this answer for background information.