Question

I am having a problem with my Windows Phone application. When I get the photo from a web service, I want to display it as an image on the page. The web service returns a byte[] as the image data.

Dispatcher.BeginInvoke(() =>
{
    tempImage = new BitmapImage();
    globalWrapper = (PhotoWrapper)JsonConvert.DeserializeObject(
                                      response.Content, typeof(PhotoWrapper));
    tempImage.SetSource(new MemoryStream(globalWrapper.PictureBinary, 0,
                                         globalWrapper.PictureBinary.Length));
    globalWrapper.ImageSource = tempImage;
    PictureList.Items.Add(globalWrapper);
});

PictureList is a ListBox defined as:

<ListBox Name="PictureList" ItemsSource="{Binding}" Margin="0,0,0,0">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                <Button Click="details_Click">
                    <Button.Content>
                        <Image Source="{Binding ImageSource}"></Image>
                    </Button.Content>
                 </Button>
            </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

Now, my question is, how do you receive a byte[] from a webservice as JSON and display it on the page? I feel like I am pretty close here but am missing something rather elementary.

Answer 1

If you’re certain that the byte[] data is valid, it could be something to do with the CacheOption property of the BitmapUmage. This property controls when data is actually loaded from the stream into the bitmap. The default is OnDemand, which only loads data from the stream when the image is displayed. You might want to try the OnLoad option instead, which loads it immediately, allowing you to close the stream.

Dispatcher.BeginInvoke(() =>
{
    globalWrapper = (PhotoWrapper)JsonConvert.DeserializeObject(
                                      response.Content, typeof(PhotoWrapper));
    tempImage = new BitmapImage();
    tempImage.BeginInit();
    tempImage.CacheOption = BitmapCacheOption.OnLoad;
    tempImage.SetSource(new MemoryStream(globalWrapper.PictureBinary, 0,
                                         globalWrapper.PictureBinary.Length));
    tempImage.EndInit();
    globalWrapper.ImageSource = tempImage;
    PictureList.Items.Add(globalWrapper);
});