EmbeddedResourceImageSource.cs

using System;
using Xamarin.Forms;
using System.Reflection;

namespace FFImageLoading.Forms
{
    /// <summary>
    /// Embedded resource image source.
    /// eg. resource://YourProject.Resource.Resource.png
    /// eg. resource://YourProject.Resource.Resource.png?assembly=[FULL_ASSEMBLY_NAME]
    /// </summary>
    public class EmbeddedResourceImageSource : ImageSource
    {
        static string _cachedMainAssembly;

        public EmbeddedResourceImageSource(Uri uri)
        {
            var text = uri.OriginalString;

            if (string.IsNullOrWhiteSpace(uri.Query))
            {
                if (_cachedMainAssembly == null)
                    _cachedMainAssembly = Application.Current?.GetType()?.GetTypeAssemblyFullName();

                Uri = new Uri(_cachedMainAssembly == null ? text : $"{text}?assembly={Uri.EscapeUriString(_cachedMainAssembly)}");
            }
            else if (!uri.Query.Contains("assembly=", StringComparison.OrdinalIgnoreCase))
            {
                var assemblyName = Application.Current?.GetType()?.GetTypeAssemblyFullName();
                Uri = new Uri(assemblyName == null ? text : $"{text}?assembly={Uri.EscapeUriString(assemblyName)}");
            }
            else
            {
                Uri = uri;
            }
        }

        public EmbeddedResourceImageSource(string resourceName, Assembly assembly)
        {
            Uri = new Uri($"resource://{resourceName}?assembly={Uri.EscapeUriString(assembly.FullName)}");
        }

        public static readonly BindableProperty UriProperty = BindableProperty.Create(nameof(Uri), typeof(Uri), typeof(EmbeddedResourceImageSource), default(Uri));

        public Uri Uri
        {
            get => (Uri)GetValue(UriProperty);
            set => SetValue(UriProperty, value);
        }

        public override string ToString()
        {
            return $"EmbeddedResource: {Uri}";
        }
    }
}