Anonymous Powershell Functions

anonymous_powershell_functions_callback.ps1

# Our Custom Logic
$CustomErrorAction = {
	param(
		$TheError
	)
	# some custom logic
	write-host $TheError -ForegroundColor 'red'
}

# A Contrived Function
Function Use-File {
	param(
		[string]$Path,
		[scriptblock]$OnError # The callback function
	)

	# test the path
	[bool]$FileExists = Test-Path $path -ErrorAction 'stop'	

	# if the path can't be found, invoke the $OnError scriptblock.
	# pass the error to the script block.
	if(!$FileExists){
		$OnError.invoke("Can not find $Path!")
	}

	# function continues to do other stuff ......
}

Use-File -Path "C:\missing\file.txt" -OnError $CustomErrorAction
# Can not find C:\missing\file.txt!