Powershell：您不能在空值表达式上调用方法

Question

目前正在构建一个脚本，该脚本从 AzureAD 收集来宾，并为我们提供自上次登录以来的天数。

当我单独运行 [int]**** 行时，它工作正常，但是当我在 ForEach 中运行时，我得到了错误

At line:8 char:5
+     [int]$LogonAge = [math]::Round(($Today - ($LastLogon.CreatedDateT ...
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

脚本如下：

$Users = Get-AzureADUser | Where-Object {$_.UserType -eq 'Guest' -and $_.AccountEnabled -eq 'True' } | Select AccountEnabled,DisplayName,ObjectID,UserType
$Today = Get-Date
$DaysOld = 30

    ForEach ($User in $Users) {
    $ObjectID = $User.ObjectId
    $LastLogon = Get-AzureADAuditSignInLogs -Top 1 -Filter "UserID eq '$ObjectID'" | select CreatedDateTime 
    [int]$LogonAge = [math]::Round(($Today - ($LastLogon.CreatedDateTime).ToDateTime($null)).TotalDays)
            if ($LogonAge -gt 30) {
            Set-AzureADUser -ObjectID $user.ObjectID -AccountEnabled $true
}
}

知道我做错了什么吗？

Answer 1

您可以检查可空性，然后进行操作。

$Users = Get-AzureADUser | Where-Object {$_.UserType -eq 'Guest' -and $_.AccountEnabled -eq 'True' } | Select AccountEnabled,DisplayName,ObjectID,UserType
$Today = Get-Date
$DaysOld = 30

    ForEach ($User in $Users) {
    $ObjectID = $User.ObjectId
    $LastLogon = Get-AzureADAuditSignInLogs -Top 1 -Filter "UserID eq '$ObjectID'" | select CreatedDateTime 
    if( $LastLogon -ne $null) # check for nullability 
    {
    [int]$LogonAge = [math]::Round(($Today - ($LastLogon.CreatedDateTime).ToDateTime($null)).TotalDays)
            if ($LogonAge -gt 30) {
            Set-AzureADUser -ObjectID $user.ObjectID -AccountEnabled $true
     }
  }
}