How to load images from specific location, not from related assembly?

Question

I have PCL based Xamarin solution. What I need to do is to load images into view in application projects. These images are in another PCL project.

Basically I have some GridView xamarin view. This view should display something like 'cards'. All data are loaded well, but images. Honestly I tried everything I could emagine - absolute path, embedded resources, relative path, windows ms-appx/// prefix. I didn't try only stream which is not very usable for me. Only web source worked.

My code:

[assembly: ExportRenderer(typeof(GridViewRoles), typeof(GridViewRolesRenderer))]
namespace StrangerParty.Windows.Renderers
{
    public class GridViewRolesRenderer : ViewRenderer<GridViewRoles, GridView>
    {
        private GridView gridView;

        protected override void OnElementChanged(ElementChangedEventArgs<GridViewRoles> e)
        {
            base.OnElementChanged(e);

            if (this.Control == null)
            {
                this.gridView = new GridView();

                StringBuilder sb = new StringBuilder();
                sb.Append("<DataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" xmlns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\">");
                sb.Append("<Grid Height=\"100\" Width=\"100\" >"); /*Background =\"#FF2E2E2E\"*/
                sb.Append("<Image x:Name=\"ImageRoleImage\" Stretch=\"UniformToFill\" Source=\"sampleForTesting.png\"/>");
                sb.Append("</Grid>");
                sb.Append("</DataTemplate>");

                DataTemplate datatemplate = (DataTemplate)XamlReader.Load(sb.ToString());

                this.gridView.ItemTemplate = datatemplate;

                SetNativeControl(this.gridView);
            }

            this.gridView.ItemsSource = Core.Instance.GameHandler.Game.Players;
        }
    }    
}

Thanks in regards for any help

Answer 1

You can load image file from PCL by using Assembly.GetManifestResourceStream . According to your requirement you need to use Converter like code behind.

Coverter

public object Convert(object value, Type targetType, object parameter, string language)
{
    var temp = new BitmapImage();
    var assembly = typeof(ImageTest.App).GetTypeInfo().Assembly;
    Stream stream = assembly.GetManifestResourceStream(value as string);
    if (stream != null)
    {
        using (var memStream = new MemoryStream())
        {
            stream.CopyTo(memStream);
            memStream.Position = 0;
            temp.SetSource(memStream.AsRandomAccessStream());
        }
    }
    return temp;
}

The next step is to create DataTemplate , To leverage converter the datatemplate can't not be loaded by XamlLoader . So you can create <ResourceDictionary> for datatemplate like codes below.

....
 xmlns:local="using:ImageTest.UWP"
    RequestedTheme="Light">
    <Application.Resources>
        <ResourceDictionary>
            <DataTemplate x:Key="MyDataTemplate">
                <Grid >
                    <Grid.Resources>
                        <local:DateToStringConverter x:Key="MyConvert"/>
                    </Grid.Resources>
                    <Image Name="MyImage" Source="{Binding imageSource , Mode=OneWay, Converter={StaticResource MyConvert}}" />
                </Grid>
            </DataTemplate>
        </ResourceDictionary>
    </Application.Resources>

MainPage.xaml

 <GridView Name="MyGridView" ItemTemplate="{StaticResource MyDataTemplate}"/>

MainPage.xaml.cs

public MainViewModel viewModel { get; set; }
  public MainPage()
  {
      this.InitializeComponent();      
      viewModel = this.DataContext as MainViewModel;
      viewModel.items.Add(new Model() { imageSource = "ImageTest.hello.jpg" });
      viewModel.items.Add(new Model() { imageSource= "ImageTest.hello.jpg" });
          MyGridView.ItemsSource = viewModel.items;
  }

So you can use the same way to create your DataTemplate by loading <Application.Resources> just like code behind.

var ItemTemplate = App.Current.Resources["MyDataTemplate"] as Windows.UI.Xaml.DataTemplate

If it doesn't work. Please have a try of my demo .