PowerShell的异常调用“替换”和“3”的说法（S）：“值不能为空

Question

虽然调用这个函数，我得到的异常呼叫零误差

代码：

---

if(Test-Path($Env:TEMP)) { 

    $hsPrefDataDirectories = Get-ChildItem "$Env:TEMP" | where {$_.Name -match "hsperfdata"} | Format-Table name -hideTableHeaders | Out-String -stream  
    $hsPrefDataDirectories = [regex]::Replace($hsPrefDataDirectories, "^\s+", '') 
    $hsPrefDataDirectories = [regex]::Replace($hsPrefDataDirectories, "\s+", ',') 
    $hsPrefDataDirectories = [regex]::Replace($hsPrefDataDirectories, ",$", '') 
    $hsPrefDataDirectories = $hsPrefDataDirectories.split(",") 
    ..... 
    $hsPrefDataDirectories = $hsPrefDataDirectories.split(",") 

---

Error: 

Exception calling "Replace" with "3" argument(s): "Value cannot be null. 
Parameter name: input" 

... 

You cannot call a method on a null-valued expression. 

Answer 1

你，因为你得到这个错误 “$ ENV：TEMP” 文件夹中没有字符串 “hsperfdata” 匹配

。

在尝试替换字符之前，请确保$ hsPrefDataDirectories不为空。