I can't do that in c# I need some help!!

Question

Hi guys
I want a part code in C# to this:
open file (any file) when press on < add to File> which take this file and write block of bytes as array[] in front of it Or tail it and save the file in same path and name(replaced)
And when i press on <read previous data> after input changed file in browse path this take the block that adds in last button read it into byte[] variable and remove it from front or tail of that file (resave it as it was)
thanks for reading all.

 
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