Can I still use Microsoft.Office.Interop assemblies with office 2013?

Question

I had to import an older project (in .Net 2) into Visual Studio 2013, it makes use of the Microsoft Primary Interop Assemblies.

Visual Studio said that I need to add references to the project. Now I went and did some reading and apparently Microsoft has only released the PIA for office 2010? (I have Office 2013)

Now what I would like to know is.

1. Can I get it to work with office 2013 and be backward compatible?
2. And if so is this a good route to go for the future? Is it going to be compatible? Because I see you need .Net 2 (at the latest) and Windows 8 comes with 4.5 and not 3 (by default) and most new computers are going to have Office 2012 or 2013.

Answer 1

PIAs are a historical artifact, required only by old .NET versions (before v4). They have been thoroughly and elegantly replaced by the "Embed Interop Types" feature, also known as the "No PIA" feature. Supported since Visual Studio 2010, you'll find it back in the Properties window when you select a reference assembly. It defaults to True. A good video that covers the underlying technology is available here.

Which is the reason that Microsoft doesn't publish the PIAs for Office 2013, they expect you to embed the interop types instead.

The feature is very desirable, it avoids your customer having to install the PIAs on his machine and for you to include them with your installer. Solving the issue when neither takes care of it, an entirely too common mishap. In addition, the PIAs for Office are very large, the great advantage of embedding the interop types is that your assembly only contain the types that you actually use. Many megabytes reduced to a few kilobytes.

The workflow is a little different. Instead of adding a reference to the Microsoft.Office.Interop assemblies as available in the Add Reference dialog, .NET Framework tab, you now use the COM tab. And pick, say, "Microsoft Excel 15.0 Object Library" to generate the interop types for a program that uses Excel. If you load an old project that previously used PIAs then just remove those reference assemblies and add them back from the COM tab.

Do note that a feature is lost, intentionally targeting an old version of Office that you don't actually have installed on your dev machine is more difficult. If that's a requirement then you still need the PIAs for that version, force the Embed Interop Types to True in the Properties window. Actually doing this is questionable, Microsoft has a hard time keeping new Office versions completely compatible with old versions. They've kept it up for 15 years now but it has been running out of steam. A worst-case scenario is targeting a newer version than you have installed on your machine, that's liable to make your program crash with very hard to diagnose exceptions like AccessViolationException.

Do note that you have to make small modifications to your code to allow it to work. The synthetic "XxxxClass" classes are not embedded, just the "Xxxx" interfaces. Simply remove the word "Class" from the new statement.

Answer 2

VS 2015 Community with Office 365 - for whatever reason the Add from the COM object does not work. The solution is go into the GAC and find the interop assemblies, copy them to a temp directory, then add to your project like any DLL.

Answer 3

Also, if you don't know by now, Windows 8 does have older versions of .NET Framework but they aren't installed by default. Go to Program Features ---> Add features to Windows ----> and the first check box should be .NET 3.0 and maybe 2.0. Note, if you are on a WSUS server you will need to tell Windows to grab the files from the Windows Update servers. Hope it helps!

Answer 4

Officially there is no backward compatibility of the PIA for Office. In fact it works.

For backward compatibility reasons I'm using the PIA for Office XP since several years and it works fine with Office XP, 2003, 2007 and 2010 (not yet tested with 2013) and on Windows XP, Vista, 7 and 8.

For compatibility with the different versions of Windows I'm using the .NET framework 3.5.

For the future... it depends of what you are doing with the PIA. If possible it is far better to directly deal with the Open XML files or to create an add-in for word/excel.

Answer 5

I just found out that the Visual Studio 2013 express does not have office-support anymore. So you need at least the pro-version to make it work.