class - 当单独的文件用于类时，管理单元从子加载，而不是在父范围内

Question

这是一个奇怪的例子，但它解决了我的问题：

文件：Foo.psm1

class Foo
{
    [OBJECT] GetSite ()
    {
        return Get-SPWeb -Identity 'http://mysharepointsite.com';
    }
}

文件：Bar.psm1

Using MODULE ".\Foo.psm1";

class Bar : Foo
{
    Bar ()
    {
        Add-PSSnapin 'Microsoft.SharePoint.PowerShell';
    }
}

安慰：

PS C:\test> Using MODULE "C:\Test\Bar.psm1";

PS C:\test> $myBar = [Bar]::new();

PS C:\test> $myBar.GetSite();
Get-SPWeb : The term 'Get-SPWeb' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was 
included, verify that the path is correct and try again.
At C:\Test\Foo.psm1:5 char:16
+         return Get-SPWeb -Identity 'http://mysharepointsite.com ...
+                ~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (Get-SPWeb:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

然而 ...

当类在同一个文件中时，它工作正常。

有什么建议么？