How do I convert struct System.Byte byte[] to a System.IO.Stream object in C#?

c# .net arrays stream

How do I convert struct System.Byte byte[] to a System.IO.Stream object in C#?

Martin Buberl

The easiest way to convert a byte array to a stream is using the MemoryStream class:

Stream stream = new MemoryStream(byteArray);

Please note that this way of creating a stream is perhaps not ideal: "This constructor does not expose the underlying stream. GetBuffer throws UnauthorizedAccessException." msdn.microsoft.com/en-us/library/e55f3s5k.aspx

@noocyte what is the ideal way then?

but you can still use stream.ToArray() if you want your byte array back.

What kind of overhead is associated with constructing a stream from the byte array like this? Memory usage is mostly what I'm wondering about.

streams created with this method can not be further expend.

Arsen Khachaturyan

You're looking for the MemoryStream.Write method.

For example, the following code will write the contents of a byte[] array into a memory stream:

byte[] myByteArray = new byte[10];
MemoryStream stream = new MemoryStream();
stream.Write(myByteArray, 0, myByteArray.Length);

Alternatively, you could create a new, non-resizable MemoryStream object based on the byte array:

byte[] myByteArray = new byte[10];
MemoryStream stream = new MemoryStream(myByteArray);

This is the best answer. It's concise and covers all the practical applications. There's a gotcha with just using the byte array based constructor as indicated here--the resulting stream is not re-sizable.

Also remember to reset stream afterward: stream.Seek(0, SeekOrigin.Begin);

Please note that the first option MemoryStream.Write is much more memory consuming then new MemoryStream(myByteArray)

Why, exactly, is that @jitbit? It's been many years since I did any .NET, so if I were going to update this answer to comment on performance, I'd need some more information.

There's extra space allocated in the MemoryStream buffer by default (just like with e.g. a list). This can be dealt with easily by using the overload that allows you to set capacity, but is only really useful if you don't expect to write any data to the stream (or if you know how much extra bytes you're likely to need). But I suspect that jitbit might be referring to the fact that a when you use the byte[] constructor, the array isn't copied - the MemoryStream refers to the array in the argument. This can be both good and bad, and it's a bit of a shame it isn't documented on MSDN :)

johnnyRose

The general approach to write to any stream (not only MemoryStream) is to use BinaryWriter:

static void Write(Stream s, Byte[] bytes)
{
    using (var writer = new BinaryWriter(s))
    {
        writer.Write(bytes);
    }
}

Vadim Ovchinnikov

Look into the MemoryStream class.

Rod Talingting

If you are getting an error with the other MemoryStream examples here, then you need to set the Position to 0.

public static Stream ToStream(this bytes[] bytes) 
{
    return new MemoryStream(bytes) 
    {
        Position = 0
    };
}

Why may one need to set position to zero, do you know ?

How do I convert struct System.Byte byte[] to a System.IO.Stream object in C#?

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