.NET Community Toolkit is a collection of helpers and APIs that work for all .NET developers and are agnostic of any specific UI platform. The toolkit is maintained and published by Microsoft, and part of the .NET Foundation.
I'm using Avalonia UI for a simple project where the MainWindow opens a dialog window. When the dialog closes, I want to get back the dialog result, which in my case is the dialog window view model. To be able to return an object when the dialog closes, I need a way to tell the OK/CANCEL buttons in the dialog to execute the Avalonia window's Close(object dialogResult) method.
To achieve that, I need to put inside the dialog view model an action like public Action<DialogWindowViewModel>? Close { get; set; }, and call it when the related command gets triggered like this:
public partial class DialogWindowViewModel : ObservableObject
{
[RelayCommand]
private void Ok()
{
Result = "OK";
Close?.Invoke(this);
}
}
In order for it to work, I need to "subscribe" to the Close action inside the view model from the dialog window code-behind:
public partial class DialogWindow : Window
{
public DialogWindow()
{
InitializeComponent();
Activated += (_, _) => ((DialogWindowViewModel)DataContext!).Close = Close;
}
}
This is the only way I found to implement it, without involving third-party frameworks like ReactiveUI, but I feel like it's leaking some View logic inside the ViewModel.
API breakdown
public sealed class RelayCommand : IRelayCommand, IObservable<Object>
{
// implements the Subscribe method
}
Then we can use the public static IDisposable Subscribe<T>(this IObservable<T> source, Action<T> onNext) extension method to add the action we want to be invoked when the command is executed.
Usage example
public partial class DialogWindow : Window
{
public DialogWindow()
{
InitializeComponent();
Activated += (_, _) => ((DialogWindowViewModel)DataContext!).OkCommand.Subscribe(Close);
}
}
Breaking change?
I'm not sure
Alternatives
Use the ReactiveCommand from ReactiveUI instead of the CommunityTollkit's RelayCommand, and subscribe from dialog's code-behind:
public partial class DialogWindow : ReactiveWindow<DialogWindowViewModel>
{
public DialogWindow()
{
InitializeComponent();
this.WhenActivated(d => d(ViewModel!.OkCommand.Subscribe(Close)));
}
}
Overview
Context
I'm using Avalonia UI for a simple project where the MainWindow opens a dialog window. When the dialog closes, I want to get back the dialog result, which in my case is the dialog window view model. To be able to return an object when the dialog closes, I need a way to tell the OK/CANCEL buttons in the dialog to execute the Avalonia window's Close(object dialogResult) method.
To achieve that, I need to put inside the dialog view model an action like
public Action<DialogWindowViewModel>? Close { get; set; }
, and call it when the related command gets triggered like this:In order for it to work, I need to "subscribe" to the
Close
action inside the view model from the dialog window code-behind:This is the only way I found to implement it, without involving third-party frameworks like ReactiveUI, but I feel like it's leaking some View logic inside the ViewModel.
API breakdown
Then we can use the
public static IDisposable Subscribe<T>(this IObservable<T> source, Action<T> onNext)
extension method to add the action we want to be invoked when the command is executed.Usage example
Breaking change?
I'm not sure
Alternatives
Use the ReactiveCommand from ReactiveUI instead of the CommunityTollkit's
RelayCommand
, and subscribe from dialog's code-behind:Additional context
No response
Help us help you
Yes, but only if others can assist