How to write bits to a file?

Question

How to write bits (not bytes) to a file with c#, .net? I'm preety stuck with it.
Edit: i'm looking for a different way that just writing every 8 bits as a byte

Answer 1

The smallest amount of data you can write at one time is a byte.

If you need to write individual bit-values. (Like for instance a binary format that requires a 1 bit flag, a 3 bit integer and a 4 bit integer); you would need to buffer the individual values in memory and write to the file when you have a whole byte to write. (For performance, it makes sense to buffer more and write larger chunks to the file).