Loading a Type Library via PowerShell and scripting Windows Live Writer

Question

I'm very new to COM and Windows programming/scripting in general. What I was trying to do is scripting Windows Live Writer; according to the documentation before I can call

  $o = New-Object -c WindowsLiveWriter.Application

I need to load the TLB first, so I should call the add-type command, unfortunately it fails:

PS C:\Users\NoWhereMan> add-type windowslivewriter.application
Add-Type : c:\Users\NoWhereMan\AppData\Local\Temp\a7ifbimo.0.cs(1) : A namespace does not directly contain members such
 as fields or methods
c:\Users\NoWhereMan\AppData\Local\Temp\a7ifbimo.0.cs(1) : >>> windowslivewriter.application
At line:1 char:9
+ add-type <<<<  windowslivewriter.application
    + CategoryInfo          : InvalidData: (c:\Users\NoWher...elds or methods:CompilerError) [Add-Type], Exception
    + FullyQualifiedErrorId : SOURCE_CODE_ERROR,Microsoft.PowerShell.Commands.AddTypeCommand

Add-Type : Cannot add type. There were compilation errors.
At line:1 char:9
+ add-type <<<<  windowslivewriter.application
    + CategoryInfo          : InvalidData: (:) [Add-Type], InvalidOperationException
    + FullyQualifiedErrorId : COMPILER_ERRORS,Microsoft.PowerShell.Commands.AddTypeCommand

for what it's worth, I'm running Windows7 x64

EDIT: x64 was the key issue, I needed to run PSH as a x86 process

Thanks

Answer 1

From help add-type:

Adds a Microsoft .NET Framework type (a class) to a Windows PowerShell session.

but windowslivewriter.application is not a .NET type.

PowerShell (PSH) directly supports COM objects, you do not need to take any special steps to load the Type Library (TLB)¹, just call the methods diretcly as given in the documentation for the component. E.g.:

$lw = New-Object -com WindowsLiveWriter.Application   
$lw.NetPost()

to launch the new post editor.

Summary: you do not need to load the TLB first.

Under 64bit Windows, you might need to ensure you are running a 32bit instance ("x86") of PSH to do this (depending if the Live Writer component runs in or out of process).

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¹ Strictly speaking, this only applies to COM types that support scripting with IDispatch, but in practice there are few that don't.