How to execute locally defined Powershell function inside DispatcherTimer Tick scriptblock?

Question

I'm new on WPF/PowerShell and I'm trying to execute a locally defined Powershell function inside a DispatcherTimer Tick scriptblock but I get this error

My code is simply :

function Get-CurrentStorageJobs
{
     My_Code 
}

$MonitorTimer = New-Object System.Windows.Threading.DispatcherTimer
$MonitorTimer.Interval = New-TimeSpan -Seconds 3
$MonitorTimer.Add_Tick({ Get-CurrentStorageJobs })
$MonitorTimer.Start()

I assumed the function didn't exist in the Tick scriptblock context so I tried to pass the function in the same way as I do with Invoke-Command scriptblock:

$MonitorTimer.Add_Tick(${ function:Get-CurrentStorageJobs })

But it failed also...

Could somebody help me ?