System.InvalidOperationException not being catched in powershell script

Question

am trying to catch a specific exception in a powershell script. Thecodeblock underneath is trying to do this, when the given exception is being thrown the script should ignore it:

try
{
    Stop-WebAppPool $webServerSettings.applicationPool
}
catch [System.InvalidOperationException]
{

}

Unfortunately this does not seem to work, I still am getting this response:

Stop-WebAppPool : Object on target path is already stopped.
At F:\Portal.Update.ps1:12 char:2
+     Stop-WebAppPool $webServerSettings.applicationPool
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [Stop-WebAppPool], InvalidOperationException
    + FullyQualifiedErrorId : InvalidOperation,Microsoft.IIs.PowerShell.Provider.StopAppPoolCommand

There are a few options I tried:

Passing the 'ErrorAction Stop' parameter value to the command. Now I do not have the error, but the script stops, that is not what I want.
Passing the 'ErrorAction SilentlyContinue' parameter value to the command. But this will only work when catching all types of exceptions, which I do not want because if the application pool does not exist, I want the exception to be thrown.

UPDATE: I found a way to work around this problem: Just read out the $_.exception variable and with GetType() get the real exception type, but having a function in a catch does not seem to right way to go:

try
{
    Stop-WebAppPool $webServerSettings.applicationPool
}
catch
{
    if ($_.Exception.GetType().Name -eq "InvalidOperationException")
    {       
        return
    }
    throw
}

Dewi Jones Dewi Jones · Accepted Answer · 2016-03-21T08:58:51

Try,

try
{
Stop-WebAppPool $webServerSettings.applicationPool -ErrorAction Stop
}
Catch
{
"Unable to stop Web App Pool"
}

-ErrorAction Stop tells PowerShell to stop when it encounters an error; this suppresses the error output you were seeing.

System.InvalidOperationException not being catched in powershell script

1 Answers