Powershell code not exiting after try catch block - powershell

Question

I have a code that downloads a file from SharePoint, edits it, uploads it back to SharePoint and finally sends a confirmation email. I have functions for each of the tasks. The code works fine.
However, I want to add error exception for a condition when if the file is open in SharePoint by some user, show error message and exit code. The issue I am experiencing is the code continues to run even if there is an exception. In the below code, the sendMail function is called even when the getSharePointFile function fails.
I have tried $ErrorActionPreference = "Stop" but with that, the catch block is not executed and my custom error MessageBox is not displayed. Thanks in advance.
Here is the relevant code:
function getSharePointFile {
Connect-PnPOnline $SharepointURL -UseWebLogin
Get-PnPFile -Url $fileRelativeURL -Path $localFilePath -FileName $fileName -AsFile -Force
}
function runCatch {
$showMessage = [System.Windows.Forms.MessageBox]::Show($_)
exit
}
try {getSharePointFile}
catch{runCatch}
try {updateAuditResults}
catch{runCatch}
try {uploadToSharePoint}
catch{runCatch}
try {sendMail}
catch{runCatch}

Answer 1

Two issues:
First, you have four independent try catch blocks, and an error handled in one has no impact on the others.
Try something like this:
try {
getSharePointFile
updateAuditResults
uploadToSharePoint
sendMail
}
catch{runCatch}
The first line to generate an error will end the batch of commands and jump to the catch block. The rest of the batch will be skipped.
The second issue you might run into is not all PowerShell cmdlets return errors when they fail. You will need to test yours to verify. Some will just display error text and continue.
More info here: https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_try_catch_finally

Answer 2

As #Mike Smith said, with the code you provided, it seems better to merge your function calls inside one try catch block.
Depending on your PowerShell version, you also need to add -ErrorAction Stop parameter to trap errors into the catch block (add it for the cmdlets, not the function call)
function getSharePointFile {
Connect-PnPOnline $SharepointURL -UseWebLogin -ErrorAction Stop
Get-PnPFile -Url $fileRelativeURL -Path $localFilePath -FileName $fileName -AsFile -Force -ErrorAction Stop
}