Using COM with Windows PowerShell 1.0

In previous chapters we have have covered the use of the .NET framework from within Windows PowerShell. In this chapter we will look at leveraging Microsoft's Component Object Model (COM) from with Windows PowerShell. In particular the issue of launching and interacting with applications and working with the Windows desktop from whithin PowerShell will be covered.

Listing Available COM Objects

Available COM objects are listed in the Windows registry. A complete list may be obtained from within Windows PowerShell by executing the following function:

function com_list
{
     $path = "REGISTRY::HKey_Classes_Root\clsid\*\progid"

     foreach ($val in dir $path)
     {
           $val.getvalue("")
     }
}

The above script will provide an extensive list of the COM objects registered in the Windows registry. A search for a specific match may be performed by piping the output of the function through to the select-string cmdlet. For example, the following command lists any COM objects names containing the word explorer:

PS C:\tmp> com_list | select-string explorer

InternetExplorer.Application.1
Shell.Explorer.2
Shell.Explorer.1

As illustrated above, there are three entries in the registry which match the criteria. One of these is Internet Explorer and the others relate to Windows Explorer.

Creating COM Object Instances in Windows PowerShell

New COM object instances are created within Windows PowerShell using the new-object cmdlet combined with the -comobject parameter. This parameter may also be abbreviated to -com. In order to avoid a any ambiguity which may result in a .NET or interop library with the same name being loaded, the -strict switch is also recommended:

new-object -comobject object name -strict

For example, to create new InternetExplorer.Application object:

PS C:\tmp> $iexplore = new-object -com InternetExplorer.Application

Listing the Properties and Methods of a COM Object

Once a new instance of a COM object has been created, it is often useful to find out the methods and properties available for that object. As with .NET objects, this can be achieved using the get-member cmdlet (also available via the gm alias). In the following example, this approach is used to identify the methods and properties of the InternetExplorer.Application object instance created in the previous section of this chapter:

PS C:\tmp> $iexplore | gm


   TypeName: System.__ComObject#{d30c1661-cdaf-11d0-8a3e-00c04fc9e26e}

Name                 MemberType Definition
----                 ---------- ----------
ClientToWindow       Method     void ClientToWindow (int, int)
ExecWB               Method     void ExecWB (OLECMDID, OLECMDEXECOPT, Variant, Variant)
GetProperty          Method     Variant GetProperty (string)
GoBack               Method     void GoBack ()
GoForward            Method     void GoForward ()
GoHome               Method     void GoHome ()
GoSearch             Method     void GoSearch ()
Navigate             Method     void Navigate (string, Variant, Variant, Variant, Variant)
Navigate2            Method     void Navigate2 (Variant, Variant, Variant, Variant, Variant)
PutProperty          Method     void PutProperty (string, Variant)
QueryStatusWB        Method     OLECMDF QueryStatusWB (OLECMDID)
Quit                 Method     void Quit ()
Refresh              Method     void Refresh ()
Refresh2             Method     void Refresh2 (Variant)
ShowBrowserBar       Method     void ShowBrowserBar (Variant, Variant, Variant)
Stop                 Method     void Stop ()
AddressBar           Property   bool AddressBar () {get} {set}
Application          Property   IDispatch Application () {get}
Busy                 Property   bool Busy () {get}
Container            Property   IDispatch Container () {get}
Document             Property   IDispatch Document () {get}
FullName             Property   string FullName () {get}
FullScreen           Property   bool FullScreen () {get} {set}
Height               Property   int Height () {get} {set}
HWND                 Property   int HWND () {get}
Left                 Property   int Left () {get} {set}
LocationName         Property   string LocationName () {get}
LocationURL          Property   string LocationURL () {get}
MenuBar              Property   bool MenuBar () {get} {set}
Name                 Property   string Name () {get}
Offline              Property   bool Offline () {get} {set}
Parent               Property   IDispatch Parent () {get}
Path                 Property   string Path () {get}
ReadyState           Property   tagREADYSTATE ReadyState () {get}
RegisterAsBrowser    Property   bool RegisterAsBrowser () {get} {set}
RegisterAsDropTarget Property   bool RegisterAsDropTarget () {get} {set}
Resizable            Property   bool Resizable () {get} {set}
Silent               Property   bool Silent () {get} {set}
StatusBar            Property   bool StatusBar () {get} {set}
StatusText           Property   string StatusText () {get} {set}
TheaterMode          Property   bool TheaterMode () {get} {set}
ToolBar              Property   int ToolBar () {get} {set}
Top                  Property   int Top () {get} {set}
TopLevelContainer    Property   bool TopLevelContainer () {get}
Type                 Property   string Type () {get}
Visible              Property   bool Visible () {get} {set}
Width                Property   int Width () {get} {set}