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Powershellで、関数内で変数値を設定し、その値を親スコープで利用できるようにする方法は？

関数を使用していくつかの変数の値を設定しようとしています。私のコードは以下です：

$BackupFile = $null
$TaskSequenceID = $null
$OSDComputerName = $null
$capturedWimPath = $null

Function Set-OsToBuild 
{
  switch ($OsToBuild)
  {
    "Win7x64"
        { 
            $BackupFile = "Win7x64-SP1.wim"
            $TaskSequenceID = "WIN7X64BC"
            $OSDComputerName = "Ref-Win7x64"
            $capturedWimPath = "$($PathToMdtShare)\Captures\$BackupFile"
        }
  }
}

問題は、$ BackupFile、$ TaskSequenceID、$ OSDComputerName、および$ capturedWimPathのこれらの値が、この関数の外では空白またはnullであることです。

これを行う適切な方法は何ですか？これらの値をこの関数内に設定し、それらの値をスクリプトの後で、親スコープで使用できるようにしたいと考えています。

functionvariablespowershellscope
9
Dbloom

変数は、関数のlocal- scopeに作成されます。これらの変数は、関数が完了すると削除されます。

Global: 
    The scope that is in effect when Windows PowerShell
    starts. Variables and functions that are present when
    Windows PowerShell starts have been created in the
    global scope. This includes automatic variables and
    preference variables. This also includes the variables, aliases,
    and functions that are in your Windows PowerShell
    profiles.

Local:  
    The current scope. The local scope can be the global 
    scope or any other scope. 

Script: 
    The scope that is created while a script file runs. Only
    the commands in the script run in the script scope. To
    the commands in a script, the script scope is the local
    scope.

出典： about_Scopes

スクリプトで変数を使用できるようにする必要がある場合は、scriptスコープに変数を書き込みます。

$BackupFile = $null
$TaskSequenceID = $null
$OSDComputerName = $null
$capturedWimPath = $null

Function Set-OsToBuild 
{
  switch ($OsToBuild)
  {
    "Win7x64"
        { 
            $script:BackupFile = "Win7x64-SP1.wim"
            $script:TaskSequenceID = "WIN7X64BC"
            $script:OSDComputerName = "Ref-Win7x64"
            $script:capturedWimPath = "$($PathToMdtShare)\Captures\$BackupFile"
        }
  }
}

（powershell-processを閉じるまで）セッション全体の値を保持したい場合は、globalスコープを使用する必要があります。

$global:BackupFile = $null
$global:TaskSequenceID = $null
$global:OSDComputerName = $null
$global:capturedWimPath = $null

Function Set-OsToBuild 
{
  switch ($OsToBuild)
  {
    "Win7x64"
        { 
            $global:BackupFile = "Win7x64-SP1.wim"
            $global:TaskSequenceID = "WIN7X64BC"
            $global:OSDComputerName = "Ref-Win7x64"
            $global:capturedWimPath = "$($PathToMdtShare)\Captures\$BackupFile"
        }
  }
}
12
Frode F.

パワーシェルabout_scopeヘルプドキュメント は、これについて読みたい内容です。

特にこのセクション：

Windows PowerShellスコープ

Scopes in Windows PowerShell have both names and numbers. The named
scopes specify an absolute scope. The numbers are relative and reflect
the relationship between scopes.


Global: 
    The scope that is in effect when Windows PowerShell
    starts. Variables and functions that are present when
    Windows PowerShell starts have been created in the
    global scope. This includes automatic variables and
    preference variables. This also includes the variables, aliases,
    and functions that are in your Windows PowerShell
    profiles. 

Local:  
    The current scope. The local scope can be the global 
    scope or any other scope. 

Script: 
    The scope that is created while a script file runs. Only
    the commands in the script run in the script scope. To
    the commands in a script, the script scope is the local
    scope.

Private:
    Items in private scope cannot be seen outside of the current
    scope. You can use private scope to create a private version
    of an item with the same name in another scope.        


Numbered Scopes:
    You can refer to scopes by name or by a number that
    describes the relative position of one scope to another.
    Scope 0 represents the current, or local, scope. Scope 1
    indicates the immediate parent scope. Scope 2 indicates the
    parent of the parent scope, and so on. Numbered scopes
    are useful if you have created many recursive
    scopes.

したがって、あなたの正確なニーズに応じて、次のいずれかを使用できます。

  1. $global:BackupFile = "Win7x64-SP1.wim"
  2. $script:BackupFile = "Win7x64-SP1.wim"
  3. $1:BackupFile = "Win7x64-SP1.wim"
4
Etan Reisner