How can I use IF using a function properly?

Question

The function below returns a result, but when I specify the value in an IF statement, it just return "Yes" whatever I put in the -eq value.

function GetRemoteLogonStatus ($computer = 'localhost') { 
if (Test-Connection $computer -Count 2 -Quiet) { 
    try { 
        $user = $null 
        $user = gwmi -Class win32_computersystem -ComputerName $computer | select -ExpandProperty username -ErrorAction Stop 
        } 
    catch { "Not logged on"; return } 
    try { 
        if ((Get-Process logonui -ComputerName $computer -ErrorAction Stop) -and ($user)) { 
            "Workstation locked by $user" 
            } 
        } 
    catch { if ($user) { "$user logged on" } } 
    } 
else { "$computer Offline" } 
}

if (getremotelogonstatus -eq "blah blah blah")
{
write-host "Yes"
}
Else
{
Write-Host "no"
}

Thanks

Answer 1

For output from a command (such as GetRemoteLogonStatus) to participate in an expression, the command call (including its arguments, if any) must be enclosed in (...), the grouping operator:

if ((GetRemoteLogonStatus) -eq "blah blah blah") {
  "Yes"
}
Else {
  "No"
}

Note:

• If the command outputs multiple objects, the -eq operator will act as a filter and, instead of returning $true or $false, will return the subarray of matching elements - see the conceptual about_Comparison_Operators help topic.

• To read more about PowerShell's two fundamental parsing modes - argument (command) mode vs. expression mode - see this answer.

Enclosure in (...) is also needed for using a command's output as an argument to another command (the example is somewhat contrived in that explicit use of Write-Output is rarely necessary):

# Pass the output from GetRemoteLogonStatus as an argument to Write-Output
Write-Output -InputObject (GetRemoteLogonStatus)

---

As for what you tried:

getremotelogonstatus -eq "blah blah blah"

• Because this snippet is parsed in argument mode, it invokes command getremotelogonstatus and passes -eq and blah blah blah as arguments to it.

• Since your command neither formally declares parameters (with a param(...) block) nor processes the automatic $args variable containing unbound positional arguments, these arguments are effectively ignored.