PS (10) > $shell.Explore("c:\") PS (11) > in Visual C#

Create Code-39 in Visual C# PS (10) > $shell.Explore("c:\") PS (11) >

At which point you should see something that looks like what s shown in figure 12.2. The method call started an Explorer window at the root of the C: drive. Now let s look at another example. We ll use the Windows() method to get a list of the Explorer windows that are open.

Launching the Windows Explorer on C:\

Thirteen are open; let s look at the first one. We ll look at the members on this object:

PS (17) > $shell.Windows() | gm TypeName: System.__ComObject#{d30c1661-cdaf-11d0-8a3e-00 c04fc9e26e} Name ---ClientToWindow ExecWB GetProperty GoBack GoForward GoHome GoSearch Navigate Navigate2 PutProperty QueryStatusWB Quit Refresh Refresh2 ShowBrowserBar Stop AddressBar Application Busy Container Document FullName FullScreen Height HWND Left LocationName LocationURL MenuBar Name Offline Parent Path ReadyState RegisterAsBrowser RegisterAsDropTarget Resizable Silent StatusBar StatusText TheaterMode ToolBar Top MemberType ---------Method Method Method Method Method Method Method Method Method Method Method Method Method Method Method Method Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Property Definition ---------void ClientToWindow (int... void ExecWB (OLECMDID, O... Variant GetProperty (str... void GoBack () void GoForward () void GoHome () void GoSearch () void Navigate (string, V... void Navigate2 (Variant,... void PutProperty (string... OLECMDF QueryStatusWB (O... void Quit () void Refresh () void Refresh2 (Variant) void ShowBrowserBar (Var... void Stop () bool AddressBar () {get}... IDispatch Application ()... bool Busy () {get} IDispatch Container () {... IDispatch Document () {g... string FullName () {get} bool FullScreen () {get}... int Height () {get} {set} int HWND () {get} int Left () {get} {set} string LocationName () {... string LocationURL () {g... bool MenuBar () {get} {s... string Name () {get} bool Offline () {get} {s... IDispatch Parent () {get} string Path () {get} tagREADYSTATE ReadyState... bool RegisterAsBrowser (... bool RegisterAsDropTarge... bool Resizable () {get} ... bool Silent () {get} {set} bool StatusBar () {get} ... string StatusText () {ge... bool TheaterMode () {get... int ToolBar () {get} {set} int Top () {get} {set}

bool TopLevelContainer (... string Type () {get} bool Visible () {get} {s... int Width () {get} {set}

And again we see lots of tantalizing things to play with. Let s look at the first item:

PS (21) > $shell.Windows()[0] Unable to index into an object of type System.__ComObject. At line:1 char:18 + $shell.Windows()[0 <<<< ]

We got an error. So what happened here If you look at the type of the object; you ll see that it s a System.__ComObject, which is the .NET mechanism for accessing COM objects. PowerShell wraps and adapts these objects, but the adaptation is not perfect, and this is one of the places it shows through.

These problems are not strictly PowerShell s fault. There are general interop problems between COM and .NET, and PowerShell inherits these problems since PowerShell uses the .NET mechanism to interoperate with COM. It can also, however, benefit from the solutions. If there is a workaround to an interop problem in .NET, that solution can generally be applied in the PowerShell world as well. And as bugs are fixed in the .NET/ COM interop code, they are also automatically fixed in PowerShell.

The PowerShell interpreter doesn t know how to index on these objects. This doesn t mean that you can t do it, however. Instead of simple indexing, you have to use the Item() parameterized property.

A parameterized property is like a method it takes arguments in parentheses just like a method, but it can also be assigned to like a property. Indexing on a COM collection in PowerShell is done using the Item() parameterized property.

Let s try it again:

PS (18) > $shell.Windows().Item(0) Application Parent Container Document TopLevelContainer Type Left Top Width Height LocationName : : : : : : : : : : : System.__ComObject System.__ComObject mshtml.HTMLDocumentClass True HTML Document 354 80 838 489 Windows PowerShell : Casting a scrip tblock to an arbitrary delegate sign ature