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ClosedXML in DLL

Aug 4, 2013 at 6:40 PM
I want to use ClosedXML in a VS2010 dll.

When I try to register (regasm /tlb MyDll.dll /codebase I get error RA0000 ... could not load file or assembly ClosedXML...

I saw something regarding ClosedXML not being "COM visible"

Does this make it impossible to use in a dll ?
Aug 4, 2013 at 8:28 PM
Edited Aug 4, 2013 at 8:29 PM
You'd have to register it for COM interop in the project's configuration window. See

I'll see if there are any downsides to it...
Aug 4, 2013 at 10:08 PM
This is exactly what I did ???
Aug 4, 2013 at 10:56 PM
I'm just returning to the project after a LONG break so forgive me for I'm a little rusty and may not be of much help.

It could be a number of things. Assuming you've downloaded the ClosedXML code and compiled it with the com visible option; then it could be you're loading it from a network shared drive. If that's not the case then I have no clue.
Aug 5, 2013 at 12:08 AM
Any ideas are much appreciated!

After hours of head-banging -- I tried to create a Windows Forms project instead... the exe threw up the same exception: could not load file or assembly ClosedXML...

I then realized that regasm had to be run on the ClosedXML.dll AS WELL AS my dll (DUH).

I'm now back in business with my class dll !!!

Thanks for your help.