VSTO Slow Performance Compared to VBA
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I am new to stackoverflow therefore I will directly start with my question.

I have few year experience with developing macros for Excel via integrated VBA and half year ago I started learning new language C#. I liked it, it's possibilities and I have also found option to develop Office Plugins directly in C# via Visual Studio (VSTO required). Problem I have is that after doing multiple tests where I tried to compare speed of addin created using C# and macro created using VBA (e.g. paste string "Test String" to each cell from A1 to A10 000 individually). The problem is that integrated VBA was multiple times faster than mentioned Addin created using Visual Studio (C#). I decided not to bother at that time with this problem however later on I came to the same problem however this time instead of cca 10 seconds (VBA) process took more than 2 minutes!
After doing research on google I found out that VSTO is not good in terms of performance especially when you require your App to interact with Excel (therefore there are ways how to workaround the problem such as saving your data into dynamic Array and then directly populating whole array into activesheet); however there ARE cases when you simply NEED to interact with excel (like I had to Unprotect many sheets within workbook dynamically...and here you simply have to say ActiveSheet.Unprotect)
My question to you guys would be, is there any way except from slow VSTO, how to create (maybe some other software) Addins for Excel/Word/Other Office products that are easily deployable?
Thank you very much.
Regards,
Robert