Try to Catch Error Exception Types

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When error handling with Try, Catch, Finally you can create conditional catch statements to target specific exceptions. Here's an example.

 

 
try {
   $wc = new-object System.Net.WebClient
   $wc.DownloadFile("https://www.contoso.com/MyDoc.doc")
}
catch [System.Net.WebException],[System.IO.IOException] {
    "Unable to download MyDoc.doc from https://www.contoso.com.
}
catch {
    "An error occurred that could not be resolved."
}

 

Look at the first Catch statement, it's looking for two specific exceptions - [System.Net.WebException] , [System.IO.IOException] . Referencing these exceptions can be a bit 'chicken and egg' though, i.e. how do you know what specific exception type to put into the catch statement? Here's how.

Generate the desired error - that'll be the egg... then use this little statement to get the exception type - the chicken.

 

 
$error[0].exception.gettype().fullname

 
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This can then be used in conjunction with a Catch statement to catch a particular exception. For example.

 

 
try {...}
catch [System.Management.Automation.MethodException] {"Overload exception"}
catch {"Generic error"}