PowerShell中調用擴展屬性失敗默默（通過更新-TypeData增補）

Question

我的問題是：

• 爲什麼這個錯誤沒有被扔到代碼？
• 我該如何讓錯誤被拋入代碼？

• 哪裏/我怎麼能自己想出來的？ /這個「功能」的文檔在哪裏？

  Function demo_problem 
  { 
      describe_global_error_variable 
      $ret_value = "be loud please".extended_property 
      write-host "returned a value=[$ret_value]." 
      describe_global_error_variable 
  } 
  
  
  Function describe_global_error_variable 
  { 
      $cnt = $Error.Count 
      write-host "`$Error .Count=[$($cnt)]." 
      $i=0 
      while ($i -lt $cnt) { 
       write-host "`$Error[$i].Exception.Message=[$($Error[$i].Exception.Message)]" 
       $i += 1 
       } 
  } 
  
  $script_block_throws = { 
       write-host "at beginning of script_block for script_block_throws. `$this=[$this]." 
       1/0 
       return $true 
       write-host "at end of script_block for script_block_throws. `$this=[$this]." 
      } 
  
  $script_block_try_catch_throw = { 
       write-host "at beginning of script_block for script_block_try_catch_throw. `$this=[$this]." 
       try 
       { 
        1/0 
        return $true 
       } 
       catch [Exception]{ 
        write-host "script_block_try_catch_throw caught an exception" 
        throw "caught an exception" 
       } 
       return $false 
       write-host "at end of script_block for script_block_try_catch_throw. `$this=[$this]." 
      } 
  
  try { 
      Update-TypeData -Value:$script_block_throws -TypeName:System.String -MemberName:extended_property -Force -MemberType:ScriptProperty 
      demo_problem 
      Update-TypeData -Value:$script_block_try_catch_throw -TypeName:System.String -MemberName:extended_property -Force -MemberType:ScriptProperty 
      demo_problem 
  } 
  catch [Exception]{ 
      write-host "exception got thrown out of the script block...." 
  } 
  
  <# 
  PS C:\ .\powershell_call_to_extended_property_fails_silently.ps1 
  $Error .Count=[0]. \ 
  at beginning of script_block for script_block_throws. $this=[be loud please]. 
  returned a value=[]. 
  $Error .Count=[1]. \ 
  $Error[0].Exception.Message=[Attempted to divide by zero.] 
  $Error .Count=[1]. \ 
  $Error[0].Exception.Message=[Attempted to divide by zero.] 
  at beginning of script_block for script_block_try_catch_throw. $this=[be loud please]. 
  script_block_try_catch_throw caught an exception 
  returned a value=[]. 
  $Error .Count=[3]. \ 
  $Error[0].Exception.Message=[caught an exception] 
  $Error[1].Exception.Message=[Attempted to divide by zero.] 
  $Error[2].Exception.Message=[Attempted to divide by zero.] 
  #> 
  

Answer 1

從PowerShell團隊得知，屬性的例外總是被屏蔽，因爲在格式化&輸出期間會頻繁使用屬性。 ScriptMethod不會屏蔽異常。雖然從調試的角度來看這是不幸的，但一般來說不是的性能要比獲得&的設置狀態要好得多。我還要補充一點，.NET開發人員不希望某個屬性出現問題。

如果您不喜歡這種行爲，請隨時在http://connect.microsoft.com網站上提交問題。我知道至少有一個PowerShell開發者不喜歡這種例外情況，即使在格式化操作之外，隱藏的也是總是。在這方面有一些客戶意見可以幫助開發者改變行爲 - 至少在嚴格模式下。

Answer 2

我真的認爲這是兩種某種範圍的問題或錯誤的。我能夠很容易地重現它。我是能夠解決問題的唯一途徑是通過一個解決辦法的方式，它看起來像這樣：

Update-TypeData -Value:$script_block_try_catch_throw -TypeName:System.String -MemberName:extended_property -Force -MemberType:ScriptProperty -ErrorAction Stop 
demo_problem 
if($error[0].Exception.Message -eq "caught an exception") 
{ 
    throw "I only exist to trigger the catch block" 
} 

我甚至想這無濟於事：

Update-TypeData -Value:{try{&$script_block_try_catch_throw}catch{throw "Error!"}} -TypeName:System.String -MemberName:extended_property -Force -MemberType:ScriptProperty -ErrorAction Stop 

我很驚訝，沒」工作。