Cannot load <Image> in App.xaml - ControlTemplate

I have the following items:

• /Assets folder containing some files like /Assets/logo_vertical_100w.png and /Assets/icon_gear.png. These files have BuildAction=None
• In the root, /App.xaml file where I declare a <ControlTemplate> like this (simplified):

<Application xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:local="clr-namespace:MyProject.Desktop"
             xmlns:base="clr-namespace:MyProject.Desktop"
             xmlns:br="clr-namespace:MyProject.Desktop.Views"
             x:Class="MyProject.Desktop.App">
[...]
<ControlTemplate x:Key="MainWindowTemplate">
    <StackPanel>
        <Image Source="/Assets/logo_vertical_100w.png" />
    </StackPanel>
</ControlTemplate>

When running I receive an error for the logo image in App.xaml:

• If I declare it with Source="/Assets/logo_vertical_100w.png":

Portable.Xaml.XamlObjectWriterException: 'Could not convert object '/Assets/logo_vertical_100w.png' (of type System.String) to {clr-namespace:Avalonia.Media.Imaging;assembly=Avalonia.Visuals}IBitmap: Relative uri /Assets/logo_vertical_100w.png without base url'

• Tried also with Source="avares://Assets/logo_vertical_100w.png", but:

Portable.Xaml.XamlObjectWriterException: 'Could not convert object '/Assets/logo_vertical_100w.png' (of type System.String) to {clr-namespace:Avalonia.Media.Imaging;assembly=Avalonia.Visuals}IBitmap: Could not load file or assembly 'Assets, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.

What’s the correct way to set Image’s source in shared templates?

[grokys]

Just investigated this and it seems to be a Portable.Xaml problem in that it’s not looking in the right place for the base URL. I will look into fixing it, but given we’re moving to a XAML compiler hopefully soon, I’m not sure how much time is worth spending on it.

In the meantime, the Source="avares://" syntax should work. However you need to actually supply the name of your assembly in the URL e.g.:

Source="avares://MyAssembly/Assets/logo_vertical_100w.png"

Note the MyAssembly part. Previously you were trying with Source="avares://Assets/logo_vertical_100w.png" and so it was looking for an assembly called Assets.

For more info see the docs: http://avaloniaui.net/docs/quickstart/assets

[Gillibald]

Is the build action set to AvaloniaResource?