How to check parameter is null in where clause in powershell - powershell

Question

I'm trying to write a PowerShell command but stucked on where clause. What i want to achieve is if parameters are not defined, where clause needs to ignore them. I tried this code but couldn't success.
I have parameters;
Param(
[parameter(position=0)]
[String]
$JobName,
[parameter(position=1)]
[String]
$JobID
)
And where clause which i tried and failed,
$Timerjob = Get-SPTimerJob | where { ($_.Id -eq $JobID) -or ($_.Title -eq $JobName) }
If $JobName or $JobID is null (or both of them), where clause should ignore them
how can i achieve this without writing multiple if clause?

Answer 1

Continuing from my comment:
To retrieve all Timer Jobs if both $JobName and $JobID are empty, you will need to add that condition to the Where-Object cmdlet:
$Timerjob = Get-SPTimerJob |Where-Object {
(!$JobName -and !$JobID) -or ($_.Id -eq $JobID) -or ($_.Title -eq $JobName)
}
This means if both $JobName and $JobID are empty, the condition (!$JobName -and !$JobID) is $True. Any condition with the -or comparison operator won't be able to change that (to $false) causing the whole condition to be true in that matter and all Timer Jobs returned.
In case you would like to make a difference between an empty string filter and a parameter that isn't supplied, you would probably want to do something like this:
$Timerjob = Get-SPTimerJob |Where-Object {
($PSBoundParameters.ContainsKey('JobName') -and $PSBoundParameters.ContainsKey('JobID')) -or
($_.Id -eq $JobID) -or ($_.Title -eq $JobName)
}
In this case you would e.g. still be able to retrieve Time Jobs with an empty title (-JobName ''), if even possible.