Getting another user’s Outlook folder…

I’ve been working on a small project to analyze report emails I receive under another Exchange account, and hit an issue that has been mentioned all over the internet where calling the GetSharedDefaultFolder MAPI function fails to work in PowerShell. The real issue lies with the fact that the interop version of the Recipient object is automatically unboxed by PowerShell to it’s base COM class. Unfortunately the interop version of GetSharedDefaultFolder can’t box it back up, and neither can PowerShell, so it all fails miserably.

I’ve read quite a few posts on the subject, mostly based on PowerShell v1.0 which have had horribly complex workarounds where you have to build C# modules and then call those from PowerShell… However, in v2.0 we can use the Add-Type command to provide the same effect and with much less work.

First, we need to reference the Outlook interop assembly:

Add-Type -AssemblyName Microsoft.Office.Interop.Outlook

Next we define the new class that will wrap the GetSharedDefaultFolder call. Note the use of the ReferencedAssemblies property on Add-Type to ensure the class will compile:

$class = @”
using Microsoft.Office.Interop.Outlook;public class MyOL
{
    public MAPIFolder GetInbox(string userName)
    {
        Application oOutlook = new Application();
        NameSpace oNs = oOutlook.GetNamespace(“MAPI”);
        Recipient oRep = oNs.CreateRecipient(userName);
        MAPIFolder inbox = oNs.GetSharedDefaultFolder(oRep, OlDefaultFolders.olFolderInbox);
        return inbox;
    }
}
“@

Add-Type $class -ReferencedAssemblies Microsoft.Office.Interop.Outlook

Now that we have this, all we have to do is instantiate the new class and get the inbox object back for a given user:

$MyOL = New-Object MyOL
$olInbox = $MyOL.GetInbox(“otherUserName”)

This is fairly simple now and also provides a good basis for further Outlook/PowerShell interop work… Hope this is of use to some of you!