We need a user control that can show Microsoft Office files (Word, Excel..). There is no need for editing them.
As I can see, there are available standalone viewer applications that can be downloaded from Microsoft site, but I am wondering if it could be embedded within an user control.
I think that there could be a COM/ActiveX component, but I cannot check that because I have Office installed, so I have to install viewers on the clean machine.
Does anyone have any experience regarding this?
If you download them from Microsoft then the viewer is probably an OCX or ActiveX component. I don't know how to use it in C#, C++, ... In Java I use jawin (http://jawinproject.sourceforge.net/) to be able to work with Word, like mail merge.
I would avoid considering the use of the Office viewers as COM object providers (even if they do register the Office COM components.) As far as I can interpret the license (I'm not a lawyer but have had to read and discuss my share of EULAs over the years), you are NOT allowed to use anything provided by the Office viewers in your application. The relevant clause of the license (right at the start):
a. General. You may install and use any number of copies of the software on your devices. You may use the software only to view and print files created with Microsoft Office software. You may not use the software for any other purpose.
I'd steer clear of gray areas in Microsoft licensing. What you want might not be expressly forbidden ($deity knows EULAs are a pain to interpret), but it's definitely not allowed by the spirit of the license. Since you might get taken to court if they want to, and since clarifying gray areas costs a lot of money, and since they have deep pockets... I think you see where I'm going with this.
If you're going to lock your users into Office, you typically have to bite the bullet and require your users to buy Office licenses.