ReactiveUI Interactions and AvaloniaUI

Introduction

New AvaloniaUI users often struggle dealing with Dialogs and returning results from Dialogs. The documentation does include a nice sample but I wanted to provide a bare minimum example on how to use ReactiveUI Interactions with AvaloniaUI.

The sample

The sample has a MainWindow with a login Button.
When you click the Button a LoginWindow is shown where you can input a username and password.
Upon closing the LoginWindow an instance of User is returned to the MainWindow
The MainWindow simply displays the Name of the User that was returned.

Basically the sample answers the question posed in the code below:

public class MainWindowViewModel : ViewModelBase
{                
	[Reactive]
	public User? User {get; set;}        

	public ReactiveCommand<Unit, Unit> LoginCommand {get; set;}
	
	public MainWindowViewModel()
	{            
		LoginCommand = ReactiveCommand.CreateFromTask<Unit, Unit>(LoginCommand_Execute);		
	}

	private async Task<Unit> LoginCommand_Execute(Unit arg)
	{
		/* How do you replace this with something that will
		 * show a LoginWindow to get a new User */
		User = new User() { Name = "Batman", Password = "JokerIsMyFriend" }; 		
		return Unit.Default;
	}
}

Architecture

While browsing through the code, the following diagram may help you better understand what is going on.

Getting & running the sample

git clone https://github.com/timothyparez/avaloniaui-reactive-interaction-sample.git
cd avaloniaui-reactive-interaction-sample
dotnet run