COM addin does not load when workbook is opened from IE

Question

We have an Office COM addin. When users don't have excel.exe running and open an Excel file from IE our addin does not load. My understanding is that IE is launching Excel as a server (aka ebedded) and that this behavior is by design.

Is there a way to change this? Our users often open Excel files from IE and they want the functionality our addin supplies available.

I have some vague memory of there being a command line parameter you can add to IE (or maybe it was a registry entry) but have not been able to find anything on this.

Thank you in advance for your insight!

yubeck1

Answer 1

Hi,

You're right, COM addin could not be loaded from Office WebApp. Generally, Office WebApp is  designed to use Office without installing it. But some advanced feature is not in it. In other words, COM addin is not in supported feature list.

Office WebApp is not just embedding Office. It's another implementation of Office. To run COM addin, people need to install Office.

You can submit the feedback to team through: http://visualstudio.uservoice.com/forums/121579-visual-studio

Best Regards,

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Forrest Guo | MSDN Community Support | Feedback to us

Answer 2

Actually my issue is a bit different. It does not involve the Office WebApps. Here is the use case more clearly

1. Excel is not running

2. User has link to Excel document on web page in IE

3. User clicks link

4. Excel is launched, Excel document is opened - However, the COM addin is not loaded.

My understanding is that this is by design. However, I am wondering if there is a workaround for it. I remember facing this issue years ago and I believe we did one of the following 1) changed a registry entry or 2) changed a command line parameter to Excel or IE.

I'm lookinng for the workaround if it exists.

Thanks again,

Answer 3

OK. Got your point. I'll look into this question further, please wait some time.

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Forrest Guo | MSDN Community Support | Feedback to us

Answer 4

Hi, I managed to get it to work. This turned to be typical deployment scenario, deploy VSTO solution to http location. A few key points to achieve the goal:

1. You will need publish the VSTO workbook project to web server.
2. The workbook need to be relative path in the html link reference. <a href="PublishedWorkbook/ExcelWorkbook1.xlsx" >VSTO WORKBOOK</a>
3. The published excel workbook location needs to be in trusted location, e.g: http://localhost:13650/PublishedWorkbook/

Let me know if there're anything unclear please, I'll try to assist.

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Forrest Guo | MSDN Community Support | Feedback to us

Answer 5

Thank you Forrest. I'll take a look at that approach.

Answer 6

Hi, have you figured out the problem?

Regards.

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Forrest Guo | MSDN Community Support | Feedback to us

Answer 7

No. We realized that our client configured IE to always launch Excel docs in Excel, not in the browser. This avoids the problem. So it was a problem that looked serious but it was really just a QA issue for us, not a production issue. We will likely revisit this issue in a month or so as we work on our next release and roll out to additional clients.

Thanks again for your help. I'll let you know if we get the issue addressed.