Best way to read a large file into a byte array in C#?
Simply replace the whole thing with:
return File.ReadAllBytes(fileName);However, if you are concerned about the memory consumption, you should not read the whole file into memory all at once at all. You should do that in chunks.
I might argue that the answer here generally is "don't". Unless you absolutely need all the data at once, consider using a Stream-based API (or some variant of reader / iterator). That is especially important when you have multiple parallel operations (as suggested by the question) to minimise system load and maximise throughput.
For example, if you are streaming data to a caller:
Stream dest = ...using(Stream source = File.OpenRead(path)) { byte[] buffer = new byte[2048]; int bytesRead; while((bytesRead = source.Read(buffer, 0, buffer.Length)) > 0) { dest.Write(buffer, 0, bytesRead); }}
I would think this:
byte[] file = System.IO.File.ReadAllBytes(fileName);