When we make modifications in .cs file how we come to know what dlls to update ?

When we make modifications in .cs file , we have to re-build the project

how we come to know what dlls to update ? and after the re-building solution only dlls are the files that need to update or anything else too ?

upload the whole bin folder

3 QUESTIONS

1) after re-building solution only dlls are the files that need to update or anything else too ?
2) there are some dll files in Obj folder too, that need to be changed with the new one too ?
3) When we make modifications in .cs file how we come to know what dlls to update ?

you need to upload the .dll  if you rebuild c# after changes - after you rebuild, look at your bin folder, you will see which ones have been updated after a rebuild by looking at the 'modified' date

if you have only changed c# in nopcommercesstore folder, nopcommercestore.dll will be the one you need to upload - of course, if you have changed, for example,  an .ascx file then you will need to upload that as well