PowerShell:无法捕获get-content引发的UnauthorizedAccessException

Question

我试图捕获System.UnauthorizedAccessException.如果用户没有对特定文件的读访问权,则会发生此异常.

$fwlog = $env:SystemRoot + "\system32\logfiles\firewall\pfirewall.log"

if(Test-Path $fwlog) 
{
    try
    {
        Get-Content -ReadCount 10 -Path $fwlog
    }

    catch [System.UnauthorizedAccessException]
    {
        Write-Host "caught"
    }
}
else 
{
    write-host "File does not exist"
}

但我不断收到此错误消息:

Get-Content : Access to the path 'C:\Windows\system32\logfiles\firewall\pfirewall.log' is denied.
At D:\SourceCode\PowerShell\FwLogParser.ps1:7 char:9
+         Get-Content -ReadCount 10 -Path $fwlog
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : PermissionDenied: (C:\Windows\syst...l\pfirewall.log:String) [Get-Content], UnauthorizedAccessException
    + FullyQualifiedErrorId : GetContentReaderUnauthorizedAccessError,Microsoft.PowerShell.Commands.GetContentCommand

我在这做错了什么？

---

谢谢回答.我仍然不明白为什么这个运行进入[Exception]而不是更具体的[System.UnauthorizedAccessException].

$fwlog = $env:SystemRoot + "\system32\logfiles\firewall\pfirewall.log"
$ErrorActionPreference = "stop"

if(Test-Path $fwlog) 
{
    try
    {
        Get-Content -ReadCount 10 -Path $fwlog 
    }

    catch [System.UnauthorizedAccessException]
    {
        Write-Host "caught"
    }

    catch [Exception]
    {
        Write-Host "Caugth generic exception"
    }
}
else 
{
    write-host "File does not exist"
}

Answer 1

try/catch只会捕获终止错误.您可以在脚本之上使用以下命令,以使所有错误成为终止错误

$erroractionPreference="stop"

@Shay Levy在这里有解释:https://stackoverflow.com/a/8381798/381149