Xamarin Forms Image to Stream

Question

My goal is to take an embedded image which is saved in each project's image folder, stream it, convert it to a byte array and save it to the device's local storage file system using PCLStorage. The part which I cannot figure out is how to stream from the embedded image.

var embeddedImage = new Image { Aspect = Aspect.AspectFit };
embeddedImage.Source = ImageSource.FromResource("applicationIcon.png");

then I could stream it if I had the path, or I could convert it to a byte [] if I had a stream. The code below does not work because the file source is not found (obviously).

string localFileUri = string.Empty;

// Get hold of the file system.
IFolder localFolder = FileSystem.Current.LocalStorage;

IFile file = await FileSystem.Current.GetFileFromPathAsync("applicationIcon.png");

using (Stream stream = await file.OpenAsync(FileAccess.Read))
{
    using (var ms = new MemoryStream())
    {
        var byteArray = ms.ToArray();

        var storeragePath = await iStorageService.SaveBinaryObjectToStorageAsync(string.Format(FileNames.ApplicationIcon, app.ApplicationId), byteArray);
        app.IconURLLocal = storeragePath;
    }
}

The only option seems to be to use some kind of resource locator, and then maintain that code for each type of project you add. Not very elegant. Is there another way?

It sounds like you're looking for embedded resources. You would then access the stream via Assembly.GetManifestResourceStream method. — Will Decker, Jan 18 '17 at 16:49
You would also have to make sure the build action on the image is embedded resource. — Will Decker, Jan 18 '17 at 16:53
Thank you deckertron_9000. That put me on the right path to figuring it out! — Mark Garcia, Jan 18 '17 at 20:11
If you have time you should write up an answer to your question on here so other people can learn as well :) — Will Decker, Jan 18 '17 at 20:16

score 7 · Accepted Answer · edited May 23 '17 at 12:08

First off, thank you to deckertron_9000 for putting me on the right path to figuring it out, and secondly these two links:

http://www.itgo.me/a/3956119637998661919/xamarin-forms-how-to-load-an-image-from-resources-into-a-byte-array

Xamarin Forms: How to use Embedded Resources in PCL Project for Image

In the end, this is what worked for me:

Firstly I added the image to a folder in my PCL. Then I made sure to change the image's Build Action to Embedded Resource.

Secondly, I added using System.Reflection;

Thirdly, this code worked for me:

string imagePath = "NameOfProject.Assets.applicationIcon.png";
Assembly assembly = typeof(NameOfClass).GetTypeInfo().Assembly;

byte[] buffer;
using (Stream stream = assembly.GetManifestResourceStream(imagePath))
{
    long length = stream.Length;
    buffer = new byte[length];
    stream.Read(buffer, 0, (int)length);

    var storeragePath = await iStorageService.SaveBinaryObjectToStorageAsync(string.Format(FileNames.ApplicationIcon, app.ApplicationId), buffer);
    app.IconURLLocal = storeragePath;
}

What do you mean of 'NameOfClass' in your second line of code? — M_Mogharrabi, Jul 07 '18 at 06:13

score 2 · Answer 2 · answered Jan 20 '17 at 11:44

 if (!CrossMedia.Current.IsCameraAvailable || !CrossMedia.Current.IsTakePhotoSupported)
        {
            await App.CurrentApp.MainPage.DisplayAlert("No Camera", ":( No camera available.", "OK");
            return;
        }

        _mediaFile = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions
        {
            Directory = "Sample",
            Name = "test.jpg"
        });

        if (_mediaFile == null)
            return;

        //ViewModel.StoreImageUrl(file.Path);

        await App.CurrentApp.MainPage.DisplayAlert("Snap", "Your photo have been added to your Items collection.", "OK");

        ImageSource = ImageSource.FromStream(() =>
        {
            var stream = _mediaFile.GetStream();
            _mediaFile.Dispose();
            return stream;
        });

Thank you Vimal. Using the CrossMedia plugin works if you have a path. In my case I didn't have a path and had to use the Assembly class. — Mark Garcia, Jan 23 '17 at 21:05

Xamarin Forms Image to Stream

2 Answers2