datetime - 为什么 Get-Date 似乎返回 DateTime 对象，但 BinarySerializer 表明它返回一个 PSObject？

Question

拿简单的HashTable :

$data = @{
    First = 'Justin';
    Last = 'Dearing';
    StartDate = Get-Date '2002-03-23';
}

键 StartDate 似乎包含 DateTime .

C:\Users\zippy\Documents> $data.StartDate.GetType().FullName
System.DateTime

但是，如果我尝试对其执行二进制序列化，我会收到一个异常，提示 PSObject不可序列化。

$ms = New-Object System.IO.MemoryStream
$bf = New-Object System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
$bf.Serialize($ms, $data)
$ms.Close()

抛出:

DocumentsException calling "Serialize" with "2" argument(s): "Type 'System.Management.Automation.PSObject' in Assembly 'System.Management.Automation, Versio
n=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' is not marked as serializable."
At C:\Users\jdearing\AppData\Local\Temp\b8967f99-0a24-41f7-9c97-dad2bc288bd9.ps1:12 char:14
+ $bf.Serialize <<<< ($ms, $data)
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException

如果我像这样对 [DateTime] 使用显式转换，则此消息将消失并且一切正常:

$data = @{
    First = 'Justin';
    Last = 'Dearing';
    StartDate = [DateTime] (Get-Date '2002-03-23');
}

Get-Date 并没有真正返回 DateTime，或者是其他一些 powershell 奇怪的东西在这里工作。

Answer 1

基于 MSDN :
PSO 对象类:
封装类型为 Object 或类型 PSCustomObject 的基础对象，以允许在 Windows PowerShell 环境中对任何对象进行一致的查看。

( get-Date '2002-03-23' ) -IS [psobject]
True

( get-Date '2002-03-23' ) -IS [datetime]
True

[datetime]( get-Date '2002-03-23' ) -IS [datetime]
True

[datetime]( get-Date '2002-03-23' ) -IS [psobject]
False