how to read the whole file directly to a stream?

[mina2040]

I know that I can read the whole file into a byte array and then convert the array to a stream using the following two lines:

byte[] fileInBytes = File.ReadAllBytes(Filename);
Stream fileInStream = new MemoryStream(fileInBytes);

But this is not efficient for my code (my code should be very fast and memory efficient). Is there any way to do this straight away without a conversion? or any other better way?

[Christian Binder]

File.Open() returns a Stream (FileStream).

[mina2040]

Thanks Christian,

It seems that my question wasn't clear enough.
I need to have the whole content of the file in Stream format because then I can pass it to a bitmap like this:

Bitmap Origbmp = new Bitmap(fileInStream);

File.Open doean't retrun a stream that contain the content of the whole file.

[Christian Binder]

Why do you have to have the whole content in a Stream? You can read/write from/into a stream like it was an array or something like that.
If you need all content read before, so your first approach would be fine.

byte[] fileInBytes = File.ReadAllBytes(Filename);
Stream fileInStream = new MemoryStream(fileInBytes);