Xamarin - Show image from base64 string

Question

I\'m pretty new to Xamarin and XAML stuff and here is what I\'ve done so far in my portable project used by Android & iPhone (only using Android):

Item.cs (loade

Answer 1

The type of your Image property should be ImageSource, not Image, as you apparently want to bind an ImageCell's ImageSource property. Besides that, calling OnPropertyChanged in a property getter never works, because the PropertyChanged event has to be fired before a binding (or any other consumer) can get a changed property value.

Instead of Image.Source="{Binding ...}, the correct binding would have to be

<ImageCell ... ImageSource="{Binding Path=Image}" />

The properties should be declared like this:

private string imageBase64;
public string ImageBase64
{
    get { return imageBase64; }
    set
    {
        imageBase64 = value;
        OnPropertyChanged("ImageBase64");

        Image = Xamarin.Forms.ImageSource.FromStream(
            () => new MemoryStream(Convert.FromBase64String(imageBase64)));
    } 
}

private Xamarin.Forms.ImageSource image;
public Xamarin.Forms.ImageSource Image
{
    get { return image; }
    set
    {
        image = value;
        OnPropertyChanged("Image");
    }
}

If you really need lazy creation of the Image property value, you could make it read-only, and make the corresponding OnPropertyChanged call in the ImageBase64 setter:

private string imageBase64
public string ImageBase64
{
    get { return imageBase64; }
    set
    {
        imageBase64 = value;
        OnPropertyChanged("ImageBase64");
        OnPropertyChanged("Image");
    } 
}

private Xamarin.Forms.ImageSource image;
public Xamarin.Forms.ImageSource Image
{
    get
    {
        if (image == null)
        {
            image = Xamarin.Forms.ImageSource.FromStream(
                () => new MemoryStream(Convert.FromBase64String(ImageBase64)));
        }
        return image;
    }
}