Unable to find suitable setter or adder for property when using binding for usercontrols

I’m trying to create a usercontrol that will accept some properties, however it appears that it fails with the error:

Error XAMLIL: Unable to find suitable setter or adder for property stringProperty of type Client:Client.test for argument Avalonia.Markup:Avalonia.Data.Binding, available setter parameter lists are:
System.String

The main window xaml is:

<Window 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:Client"
        x:Class="Client.MainWindow"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="600"
        Title="Title" Background="LightGray" Width="800" Height="600">
    <TextBlock Text="{Binding dataString}"/>
    <local:test stringProperty="{Binding dataString}"/>
</Window>

MainWindows ViewModel is:

namespace Client
{
	public class MainWindowViewModel
	{
		public string dataString{ get{ return("sample text");} }
	}
}

The test xaml is:

<UserControl 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"
             x:Class="Client.test" mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450">
	<TextBlock Text="Some text"/>
</UserControl>

And the code-behind for test is:

namespace Client
{
	public class test : UserControl
	{
		public string stringProperty { get; set; }

		private void InitializeComponent()
		{
			AvaloniaXamlLoader.Load(this);
		}

		public test()
		{
			this.InitializeComponent();
		}
	}
}

I have also tried to use direct/attached/styled/etc. properties, but nothing seems to have helped.

One thing I have noticed however, is that when not using databinding in the main window, the code does compile and work as expected. I left out bindings in the usercontrol and related code to make sure that wasn’t causing the issue, and when using just a static string the property is indeed set properly.

I’m fairly new to Avalonia and mvvm so I might have misconceptions about how usercontrols and their properties work. So if this is intended behavior and I’m using the wrong control or something do tell me, as I have been stuck for the past few days.

[MarchingCube]

@grokys I guess another part that needs to be covered in updated documentation for properties.

[Gillibald]

You need to fulfill the naming convention.

string String { get.... ; set....} AvaloniaProperty StringProperty