Programming Microsoft Outlook with Visual Studio .NET

The following whitepapers are essential for developers writing Office Add-ins that are digitally signed with the help of a shim. Unfortunately, digital signatures do not always determine whether Outlook Add-ins are trusted or untrusted. The Outlook E-mail Security Update and the Administrative Form determine the level of trust and access to both the Outlook Object Model (OOM) and Collaboration Data Objects (CDO).

Deployment of Managed COM Add-Ins in Office XP
Isolating Office Extensions with the COM Shim Wizard
Secure Deployment of Managed COM Add-Ins in Office XP
Using the COM Add-in Shim Solution to Deploy Managed COM Add-ins in Office XP
Using the Smart Tag Shim Solution to Deploy Managed Smart Tags in Office XP

Rebuilding the Outlook Interop Assembly

The preferred means of referencing Outlook is with an Outlook Primary Interop Assembly (PIA). The Outlook PIA is only available for Outlook 2002 and Office XP. If you are targeting both Outlook 2000 and 2002, you will have to rebuild the Outlook Assembly used for COM Interop. If you plan to build an event-aware application, you must rebuild Interop.Outlook.dll. The following article applies to Excel Events. You can use the steps outlined in this article to modify Interop.Outlook.IL and rebuild Interop.Outlook.dll.

PRB: Error Using WithEvents or Delegates to Handle Excel Events from Visual Basic .NET or Visual C# .NET (Q316653)

The sequence of steps to rebuild Interop.Outlook.dll is as follows:

Save and close your Visual Studio .NET project.
Open a Visual Studio .NET command prompt and change the directory to the output directory of your project (for example, project name \bin for a Visual Basic project or project name \bin\release for a C# project).
Use Ildasm.exe to extract the intermediate language from the Outlook interop assembly, as follows:
ildasm.exe /source Interop.Outlook.dll /output=Interop.Outlook.il
Open Interop.Outlook.il in a text editor such as WordPad and search for occurrences of "_SinkHelper". Change the access privileges of the _SinkHelper classes from Private to Public, and then save and close Interop.Outlook.il.
Open your project in Visual Studio .NET.
In Visual Studio .NET Solution Explorer, right-click Outlook in the list of project references and then click Properties . Change the Copy Local property to False .

IMPORTANT : This step is required. If you do not set the Copy Local property of the reference to False , Visual Studio .NET regenerates the interop assembly when you compile the project.
At the Visual Studio .NET command prompt, use Ilasm.exe with the /dll switch to recompile the intermediate language file into an interop assembly, as follows:
ilasm.exe /dll Interop.Outlook.il /output=Interop.Outlook.dll

Office XP Primary Interop Assembly

The Office XP Primary Interop Assembly (PIA) is finally available for download. The Office XP PIA provides the preferred Interop Assemblies for developers who are targeting the Office XP platform. At this time, Microsoft does not offer a PIA for Office 2000. Visit the following to download the Office XP PIA:

http://www.microsoft.com/downloads/details.aspx?familyid=C41BD61E-3060-4F71-A6B4-01FEBA508E52&displaylang=en

For an overview and discussion of some known issues with the Primary Interop Assembly, see the following:

Office XP Primary Interop Assemblies Known Issues
Working with the Office XP Primary Interop Assemblies

Note: The Office XP Primary Interop Assembly does not fix the design-time problem of "[Name] ambiguous across inherited interfaces." For Outlook Interop, there are several methods that cause the error to appear in the Visual Studio .NET Task List. These methods include Explorer.Close and Inspector.Close. The only way to resolve the design-time error is to use the RCW ExplorerClass and InspectorClass in your declarations of event-aware objects. For a discussion of the problem, see the following:

BUG: Visual Basic .NET "'[Method]' is ambiguous across the inherited interfaces" Error Message When Using Office Automation

Last Modified: Sunday, November 20, 2005