Has Microsoft updated Windows and Office software with .NET-type dll assemblies?

Question

Has Microsoft updated Windows and Office software with .NET-type dll assemblies?

George Seese 1

In Visual Studio, Reference Manager includes COM objects for references. Does Windows and Office still use their original dll files? I've read that .NET .dll assemblies have advantages over older kinds of dll files (COM, Win32?). How are "wrappers" used? Is there an article or book that explains this? The extension "dll" can represent a variety of assemblies. It can be Calculate.dll, a Class Library project I made that has one simple method. Or it can be a collection of Excel stuff in Microsoft.Office.Interop.Excel.dll. Why didn't Microsoft assign a new extension (e.g. .dlla) for the different .NET assembly dll files, in the way Excel released .xlsx and .xlsm?

Xingyu Zhao-MSFT 5,341 Reputation points

2020-12-07T09:42:40.84+00:00

Hi @George Seese ,
Thank you for posting here.
According to your description, I have two questions to confirm with you.
What does 'wrappers' mean? Could you provide more details?
What features do you want new extensions(such as .dlla) have?
George Seese 1 Reputation point

2020-12-07T15:42:21.003+00:00

(1) Wrappers. This word appeared when I was trying to add a reference to Excel in a Visual Studio 2019 C# project (which should be easy). In the Reference Manager, Excel is mentioned in COM but not in NET assemblies (Community
edition). I found a dll file in my Windows 10 at C:\Windows\assembly\GAC_MISL... Microsoft.Office.Interop.Excel.dll. I Added that file and my C# project was satisfied. But when I mentioned this option in another forum, a person said
those dlls (I assume he referred to the GAC_MISL folder) are wrappers around the Office COM". From that I got the impression Office COM is older-style that need [help] wrappers to work with current .NET. So I'm curious if Microsoft
will update Office and Windows to .NET-assembly style dll.

(2) .dlla. Articles about .NET explain the new dll assemblies have metadata etc. that resolve problems with older-style dll. If they are that much different, I'm curious why they didn't assign a new extension.
Xingyu Zhao-MSFT 5,341 Reputation points

2020-12-08T06:10:31+00:00

Hi @George Seese ,
Hope the following reference is helpful for the first question.

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

Xingyu Zhao-MSFT 5,341 Reputation points

2020-12-07T09:42:40.84+00:00

Hi @George Seese ,
Thank you for posting here.
According to your description, I have two questions to confirm with you.
What does 'wrappers' mean? Could you provide more details?
What features do you want new extensions(such as .dlla) have?
George Seese 1 Reputation point

2020-12-07T15:42:21.003+00:00

(1) Wrappers. This word appeared when I was trying to add a reference to Excel in a Visual Studio 2019 C# project (which should be easy). In the Reference Manager, Excel is mentioned in COM but not in NET assemblies (Community
edition). I found a dll file in my Windows 10 at C:\Windows\assembly\GAC_MISL... Microsoft.Office.Interop.Excel.dll. I Added that file and my C# project was satisfied. But when I mentioned this option in another forum, a person said
those dlls (I assume he referred to the GAC_MISL folder) are wrappers around the Office COM". From that I got the impression Office COM is older-style that need [help] wrappers to work with current .NET. So I'm curious if Microsoft
will update Office and Windows to .NET-assembly style dll.

(2) .dlla. Articles about .NET explain the new dll assemblies have metadata etc. that resolve problems with older-style dll. If they are that much different, I'm curious why they didn't assign a new extension.
Xingyu Zhao-MSFT 5,341 Reputation points

2020-12-08T06:10:31+00:00

Hi @George Seese ,
Hope the following reference is helpful for the first question.

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

Answer 1

Cheong00 3,426

I think there is major misunderstanding here.

The Primary-Interop-Assembly (PIA) is a bunch of .NET libraries for including reference to MS Office 2007+. It's for use of Office Automation as what you use for at the time of VB6. The primary advantage of using it instead of directly "Add reference" to the COM DLL is that, it's registered in the Global Assembly Cache (GAC) and it'll automatically load the correct version of Office for you (Many applications in MS Office allow side-by-side installation with earlier versions).

George Seese 1 Reputation point

2020-12-08T14:54:19.487+00:00

@Cheong00 I agree there is a major misunderstanding.
You introduce a new term "PIA" as a "bunch of .NET libraries".
I do not see "PIA" in Visual Studio Reference Manager.
If I select COM item "Microsoft Excel 16.0 Object Library" it creates a reference with a path to the GAC_MISL folder I mentioned in the initial Question.
So I do not understand your saying PIA has an advantage to COM DLL.
I only want to utilize Office Excel in a VS C# application.
I do not want to add features to Excel.
My development machine and run machine are the same.
I have only one version of Office/Excel on that machine.
I don't have "standing" to ask about Windows and Office having .NET-type assemblies. I really do not need to know that for my VS project to work.
I'm only curious if Windows and Office have been or will be updated to have the advantages of .NET assemblies.

Answer 2

Cheong00 3,426

PIA for Office 2007 and 2010 are made as downloadable package from Microsoft website, and later versions are installed as ".NET Programmability Support" feature of your office installation. As you can see these are tightly coupled with the corresponding Office version (unless you enabled binding redirection), that's why I said you can load the correct version of Office by using PIA.

This is the major reason of using PIA over the newer "Embed Interop Types" feature mentioned on the link provided by XingyuZhao. Although it's true that backward compatibility of the Office libraries is good, the applications themselves to some extent does not. Say on a previous company, I can only get the "print cheque" function print correctly on a specific printer from Excel 2007, despite checked the custom paper setting and print boundaries are set exactly the same.

George Seese 1 Reputation point

2020-12-09T15:44:53.137+00:00

@Cheong00 This does not directly answer my question. But since you introduce PIA,
How do I specify PIA in a Visual Studio Reference Manager?
I only see NET assemblies and COM in my Community edition.
Microsoft Excel is available only in the COM section, and it generates a dll file with path to Windows GAC_MISL.
I wonder if my "confusion" is due to what is missing on Community edition of VS?
Xingyu Zhao-MSFT 5,341 Reputation points

2020-12-11T01:45:56.637+00:00

Hi @George Seese ,

As suggested in the document : The Assemblies tab lists all .NET assemblies that are available for referencing. The Assemblies tab doesn't list any assemblies from the global assembly cache (GAC) because assemblies in the GAC are part of the run-time environment.

Check the following reference : Help understanding the GAC_MSIL directory
George Seese 1 Reputation point

2020-12-11T15:23:52.857+00:00

Hi @Xingyu Zhao-MSFT
(1) Ms Reference Manager document: In my VS 2019 Community, if I select Assembly, NET, I do not find an item for Microsoft Excel. But if I select COM I find it. If I check that, it adds an Excel reference that works in the project. That reference has path to GAC_MSIL (runtime). The Ms document implies a problem using the GAC dll that I do not understand. It does not explain if the dev and target machine are the same, is there a problem? Note: In a 2015 youtube vid, a user demonstrates finding Ms Excel in NET Assemblies but it does not work now in my VS.

(2) "Understanding the GAC", it's 2008. What has Ms changed since then?

Due to these complications, I'm considering switching to EPPLus that is easier and has advantage of the "using" statement, as done in newer SQL VS C# projects.

Apparently the answer to my question is No, Ms is not converting Office or Windows to NET.

Has Microsoft updated Windows and Office software with .NET-type dll assemblies?

2 answers

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