Powershell捕获异常类型 [英] Powershell catching exception type

问题描述

是否有方便的方法来捕获异常和内部异常以进行尝试捕获?

Is there a convenient way to catch types of exceptions and inner exceptions for try-catch purposes?

示例代码:

$a = 5
$b = Read-Host "Enter number" 
$c = $a / $b #error if $b -eq 0
$d = get-content C:\I\Do\Not\Exist

第3行将生成带有内部异常的运行时错误(已修复此命令$ Error [1] .Exception.InnerException.GetType())，第4行将生成标准"(?)类型异常($ Error [0] .Exception.GetType()).

Row #3 will generate a runtime error with an inner exception ( fixed this command $Error[1].Exception.InnerException.GetType()), row #4 will generate a "standard"(?) type of exception ($Error[0].Exception.GetType()).

是否可以通过同一行代码从这两者中获得所需的结果?

Is it possible to get the desired result from both of these with the same line of code?

Ad1:第3行出现错误

Ad1: error from row 3

At -path-:3 char:1

+ $c = $a / $b #error if $b -eq 0
+ ~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], RuntimeException
    + FullyQualifiedErrorId : RuntimeException

Ad2:第4行出现错误

Ad2: error from row 4

get-content : Cannot find path 'C:\I\Do\Not\Exist' because it does not exist.

At -path-:4 char:6

+ $d = get-content C:\I\Do\Not\Exist

+      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : ObjectNotFound: (C:\I\Do\Not\Exist:String) 
[Get-Content], ItemNotFoundException    
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.GetContentCommand

为了清楚起见，我希望结果以某种方式返回DivideByZeroException和ItemNotFoundException

To make it clear, I want the result to return DivideByZeroException and ItemNotFoundException in some way

推荐答案

首先，您可以显式捕获特定的异常类型:

First of all, you can explicitly catch specific exception types:

$ErrorActionPreference = "Stop"
try {
    1/0
}
catch [System.DivideByZeroException] {
    $_.Exception.GetType().Name
}
try {
    gi "c:\x"
}
catch [System.Management.Automation.ItemNotFoundException] {
    $_.Exception.GetType().Name
}

DivideByZeroException 基本上只是 RuntimeException 的InnerException，从理论上讲，InnerExceptions可以无休止地嵌套:

The DivideByZeroException is basically just the InnerException of RuntimeException, and theoretically, the InnerExceptions could be endlessly nested:

catch {
    $exception = $_.Exception
    do {
        $exception.GetType().Name
        $exception = $exception.InnerException
    } while ($exception)
}

但，您可以作为特殊情况处理 RuntimeException .甚至PowerShell也会这样做.看第一个代码示例.即使指定了 inner 异常的类型，也会达到catch块.

BUT you can handle RuntimeException as a special case. Even PowerShell does so. Look at the first code example. The catch-block is reached even though the type of the inner exception is specified.

您可以自己做类似的事情:

You could do something similar yourself:

catch {
    $exception = $_.Exception
    if ($exception -is [System.Management.Automation.RuntimeException] -and $exception.InnerException) {
        $exception = $exception.InnerException
    }
    $exception.GetType().Name
}

注意，如果要捕获两个异常，则每个命令需要一个try-catch.否则，如果第一个失败，则第二个将不会执行.另外，您还必须为"Stop" 指定 $ ErrorActionPreference 来捕获非终止异常.

NOTE that you need one try-catch per command, if you want to catch both exceptions. Else the 2nd will not be executed if the 1st one fails. Also you have to specify $ErrorActionPreference to "Stop" to catch also non-terminating exceptions.

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