I already did the process - Importing dll file in Dotpeek and Exporting Assembly to Project, Now I can modify dll file in VS 2015, but how to recompile the project and use recompiled dll file again in existing project.. I tried with building project in vs 2015 but it displays lots of compile time errors, Please help
Thanks :)
Rather unfortunately, there is no decompiler that will produce code that compiles for an assembly containing more than a couple of classes.
So you might want to try JustDecompile + Reflexil to do your edit. The advantage of this approach is that only the part you edit will get changed and the rest of the assembly will remain the same as original.