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

问题描述

使用PowerShell和 System.DirectoryServices ，我得到了一个类似下面的对象：

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()

我可以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。我如何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：这个对象实际上库（ActiveD），但由于某种原因，我无法使用它开箱即用，作为一个不同的问题（通过PowerShell和脚本Windows Live Writer加载类型库）建议应该是这样。

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.

这里是一个显示如何获得这样一个对象的单行：

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反射不正确这些对象的属性和方法。要获得属性和方法，我使用一些包装函数。下面是一个例子：

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， strong> @（）。

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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