c# UWP - Convert byte array to InMemoryRandomAccessStream/IRandomAccessStream

Question

I have a problem converting byte array to InMemoryRandomAccessStream or IRandomAccessStream in windows 8?

This is my code, but It doesn't work :

internal static async Task<InMemoryRandomAccessStream> ConvertTo(byte[] arr) 
{
    InMemoryRandomAccessStream randomAccessStream = new InMemoryRandomAccessStream();
    
    Stream stream = randomAccessStream.AsStream();
    
    await stream.WriteAsync(arr, 0, arr.Length);
    await stream.FlushAsync();

    return randomAccessStream;
}

And I created the RandomAccessStreamReference and set the requst datapack in order to share the image to other app

private static async void OnDeferredImageStreamRequestedHandler(DataProviderRequest Request) 
{
    DataProviderDeferral deferral = Request.GetDeferral();
    InMemoryRandomAccessStream stream = await ConvertTo(arr);
    
    RandomAccessStreamReference referenceStream =
            RandomAccessStreamReference.CreateFromStream(stream);
    
    Request.SetData(referenceStream);
}

There's no exception but I can't use the result image byte array

I think there's an error when converting byte[] to InMemoryRandomAccessStream, but it doesn't throw an exception.

Anybody know how to implement it?

if anyone knows how to convert the byte array to IRandomAccessStream, it's also appreciated

Pigeon

What exactly is wrong with the code you have? – Ratio

Please check this & tell me if you can solve the issue. – Orvalorvan

Answer 1

Add the using statement at the top of the document.

using System.Runtime.InteropServices.WindowsRuntime;
internal static async Task<InMemoryRandomAccessStream> ConvertTo(byte[] arr)
{
    InMemoryRandomAccessStream randomAccessStream = new InMemoryRandomAccessStream();
    await randomAccessStream.WriteAsync(arr.AsBuffer());
    randomAccessStream.Seek(0); // Just to be sure.
                    // I don't think you need to flush here, but if it doesn't work, give it a try.
    return randomAccessStream;
}

Pleopod

Answer 2

On Windows 8.1 it's even easier as we added the AsRandomAccessStream extension method:

internal static IRandomAccessStream ConvertTo(byte[] arr)
{
    MemoryStream stream = new MemoryStream(arr);
    return stream.AsRandomAccessStream();
}

Luz

This seems not to work for some scenarios, as described in #22332717 – Crissycrist

Answer 3

In one line:

internal static IRandomAccessStream ConvertTo(byte[] arr)
{
    return arr.AsBuffer().AsStream().AsRandomAccessStream();
}

Crissycrist

It looks like an action that copies the data three times. You need to check that this is not happening in order for the answer to be usable. – Wives