Powershell范围处理v2 / v3的未记录更改？ [英] Undocumented changes to Powershell Scope handling v2/v3?

问题描述

背景：我一直在撰写一个powershell脚本，用于将Windows Server '08（使用Powershell 2.x）上的Sharpoint 2010实例的文件迁移到Windows Server '12上的Sharepoint 2013实例（与Powershell 3.x）。我有这个工作，但我注意到了如何处理范围的变化。

问题：我有以下代码可以在两个PSSession上运行（ $ param 是参数值的散列表）

  Invoke-Command -session $ Session -argumentlist $ params -scriptblock`
 {
 Param（$ in）
 $ params = $在＃存储参数在远程会话
 
＃需要使用提升的权限运行以访问sharepoint farm 
＃drops cli stdout support（no echo to screen ...）
 [Microsoft.SharePoint.SPSecurity] :: RunWithElevatedPrivileges（
 {
＃开始获取网站和web对象
 $ site = get-spsite（$ params [SiteURL]）
}）
} 
 我注意到，在分配给 $ site 的PS 2.x远程会话中，也分配给在 Invoke-Command 的范围内的相同变量，即任一范围获得通过或者共享sa我的范围分配给 $ site 的PS 3.x远程会话中但是不更改 Invoke-Command （true child scope）。
 
 
 
 我的解决方案：我写了一个函数来计算在每个服务器上调用它的正确范围，然后使用返回值作为 Get-Variable 和 Set-Variable 的 -Scope 选项。这解决了我的问题，并允许赋值和访问变量。
 函数GetCorrectScope 
 {
＃scoping在版本3中的powershell 
＃的版本2和3之间更改，我们需要在
＃parent和本地范围之间传输变量。 
 if（$ psversiontable.psversion.major -gt 2）
 {
 $ ParentScope = 1＃上一级，powershell版本> = 3 
} else 
 {
 $ ParentScope = 0＃当前级别，powershell版本< 3 
} 
 
 $ ParentScope 
} 
  
 问题：微软所记录的哪里有哪些地方？ （我在TechNet上的 about_scope 找不到它，它说它适用于2.x和3.x，是我在其他问题中看到的标准参考。）
 
 
 
另外，是否有更好/正确的方式这个？
解决方案
 WMF 3发行说明在更改WINDOWS POWERSHELL LANGUAGE一节中有记录。 p> 
 
 
 
 
作为委托人执行的脚本块在自己的范围内运行
 
 
 
 
 
  Add-Type @
 public class Invoker 
 {
 public static void Invoke（System.Action< int> func）
 {
 func（1）; 
} 
} 
@ 
 $ a = 0 
 [Invoker] :: Invoke（{$ a = 1 $）
 $ a 
 
 Windows PowerShell 2.0中返回1 
 Windows PowerShell 3.0中返回0 
  
 
Background: I've been writing a powershell script to migrate files from a Sharpoint 2010 instance on Windows Server '08 (with Powershell 2.x) to a Sharepoint 2013 instance on Windows Server '12 (with Powershell 3.x). I have that working but I noticed a change in how scope is handled.

Issue: I have the following code that gets run on both PSSessions ($param is a hashtable of parameter values)
Invoke-Command -session $Session -argumentlist $params -scriptblock `
{
    Param ($in)
    $params = $in # store parameters in remote session

    # need to run with elevated privileges to access sharepoint farm
    # drops cli stdout support (no echo to screen...)
    [Microsoft.SharePoint.SPSecurity]::RunWithElevatedPrivileges(
    {
        # start getting the site and web objects
        $site = get-spsite($params["SiteURL"])
    })
}
I noticed that in the PS 2.x remote session that assigning to $site  also assigned to the same variable in Invoke-Command's scope, i.e. either scope gets passed or they share the same scope. BUT in the PS 3.x remote session assigning to $site does not change the value in Invoke-Command (true child scope).

My Solution: I wrote a function to compute the correct scope on each server which it calls and then uses the return value as an input to Get-Variable and Set-Variable's -Scope option. This solved my problem and allows assignment and access of the variables.
Function GetCorrectScope
{
    # scoping changed between version 2 and 3 of powershell
    # in version 3 we need to transfer variables between the
    # parent and local scope.
    if ($psversiontable.psversion.major -gt 2)
    {
        $ParentScope = 1 # up one level, powershell version >= 3
    }else
    {
        $ParentScope = 0 # current level, powershell version < 3
    }

    $ParentScope
}
The Question: Where, if anywhere, is this documented by Microsoft? (I couldn't find it in about_scope on TechNet, which says it applies to both 2.x and 3.x and is the standard reference I've seen in other questions).

Also, is there a better/proper way to do this?
解决方案
It is documented in the WMF 3 Release Notes in the section "CHANGES TO THE WINDOWS POWERSHELL LANGUAGE".

  
Script blocks executed as delegates run in their own scope


Add-Type @"
public class Invoker
{
    public static void Invoke(System.Action<int> func)
    {
        func(1);
    }
}
"@
$a = 0
[Invoker]::Invoke({$a = 1})
$a

Returns 1 in Windows PowerShell 2.0 
Returns 0 in Windows PowerShell 3.0


                        
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