使用 PowerShell 包装现有的 COM 对象 [英] Use PowerShell to wrap an existing COM object

问题描述

使用 PowerShell 和 System.DirectoryServices，我得到了一个如下所示的对象:

Using PowerShell and System.DirectoryServices, I've been given an object that looks like this:

   TypeName: System.__ComObject

Name                      MemberType Definition
----                      ---------- ----------
CreateObjRef              Method     System.Runtime.Remoting.ObjRef CreateObjRef(type requestedType)
Equals                    Method     bool Equals(System.Object obj)
GetHashCode               Method     int GetHashCode()
GetLifetimeService        Method     System.Object GetLifetimeService()
GetType                   Method     type GetType()
InitializeLifetimeService Method     System.Object InitializeLifetimeService()
ToString                  Method     string ToString()

我能找到的所有示例代码都涉及从 PowerShell 创建新的 COM 对象，而不是包装已返回的现有对象.我怎样才能有效地处理这个对象(枚举和使用实际的属性和方法)?

All example code that I can find deals with creating new COM objects from PowerShell, not wrapping existing objects that have been returned. How can I usefully deal with this object (enumerate and use the actual properties and methods)?

注意:这个对象实际上确实有一个类型库(ActiveDs")，但由于某种原因我无法直接使用它，作为一个不同的问题(通过 PowerShell 加载类型库并编写 Windows Live Writer 脚本) 建议应该是这样的.

Note: this object actually does have a type library ("ActiveDs"), but for some reason I am unable to use it out of the box, as a different question (Loading a Type Library via PowerShell and scripting Windows Live Writer) suggests should be the case.

这是一个单行代码，展示了如何获取这样的对象:

Here is a one-liner showing how to get such an object:

((new-object DirectoryServices.DirectoryEntry -a '
LDAP://somedc').Properties.GetEnumerator() |?{$_.PropertyName -eq 'usnChanged' }).Value[0] | Get-Member

推荐答案

PowerShell 反射不能正确看到"这些对象的属性和方法.为了获得属性和方法，我使用了一些包装函数.这是一个例子:

PowerShell reflection doesn't properly "see" these objects' properties and methods. To get to the properties and methods, I use some wrapper functions. Here is an example:

function Get-Property {
  param(
    [__ComObject] $object,
    [String] $propertyName
  )
  $object.GetType().InvokeMember($propertyName,"GetProperty",$NULL,$object,$NULL)
}

function Set-Property {
  param(
    [__ComObject] $object,
    [String] $propertyName,
    $propertyValue
  )
  [Void] $object.GetType().InvokeMember($propertyName,"SetProperty",$NULL,$object,$propertyValue)
}

function Invoke-Method {
  param(
    [__ComObject] $object,
    [String] $methodName,
    $methodParameters
  )
  $output = $object.GetType().InvokeMember($methodName,"InvokeMethod",$NULL,$object,$methodParameters)
  if ( $output ) { $output }
}

$ADS_ESCAPEDMODE_ON = 2      # see ADS_ESCAPE_MODE_ENUM
$ADS_SETTYPE_DN = 4          # see ADS_SETTYPE_ENUM
$ADS_FORMAT_X500_PARENT = 8  # see ADS_FORMAT_ENUM

$Pathname = New-Object -ComObject "Pathname"
# store initial EscapedMode
$escapedMode = Get-Property $PathName "EscapedMode"
# Enable all escaping
Set-Property $PathName "EscapedMode" @($ADS_ESCAPEDMODE_ON)
Invoke-Method $Pathname "Set" @("CN=Ken Dyer,OU=H/R,DC=fabrikam,DC=com",$ADS_SETTYPE_DN)
Invoke-Method $Pathname "Retrieve" @($ADS_FORMAT_X500_PARENT)
# outputs 'OU=H/R,DC=fabrikam,DC=com'
$escapedMode = Set-Property $PathName "EscapedMode" @($escapedMode)
# set EscapedMode property back to initial value

请注意，Set-Property 和 Invoke-Method 使用数组作为它们的最终参数，因此我在调用这些函数时使用 @( ).

Note that the Set-Property and Invoke-Method use an array as their final parameter, so I use @( ) when calling those functions.

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