MvvmDialogs.Avalonia.Ursa 0.1.0

MvvmDialogs.Avalonia.Ursa

An implementation of HanumanInstitute.MvvmDialogs using Ursa.Avalonia as UI.

Usage

Use UrsaWindowDialogService if you want to show dialog as a Window, and UrsaOverlayDialogService as an Overlay Dialog.

Screenshots

Window dialog

Overlay dialog

DialogContext

A problem of using MVVM Dialog is how to identify the owner Window, especially when your APP has multiple windows.

DialogContext can be used to find owner Window. Implement IDialogContextOwner interface in your ViewModel class, set DialogContext.ToplevelHashCode as the HashCode of the window you want to show dialog in, and set this as owner ViewModel when show dialog. The manager would automatically find the right window.

DialogContext.HostId is used to find OverlayDialogHost when using UrsaOverlayDialogService. This is required only when you are using a OverlayDialogHost in you control; if you use UrsaWindow or UrsaView, just set the ToplevelHashCode as the owner window's hashcode, Ursa can find the right window and OverlayDialogHost to show dialog in.

Best Practices

When you are using IoC container, the best way to use DialogContext is implementing a DialogContextProvider:

public class DialogContextProvider
{
    public DialogContext DialogContext { get; set; } = new DialogContext(0, null);
}

Register the DialogContextProvider as scoped service. In ViewLocator, set the DialogContext when create a new window:

public class ViewLocator : StrongViewLocator
{
    private readonly IDialogContextProvider _dialogContextProvider;
    public ViewLocator(IDialogContextProvider dialogContextProvider)
    {
        _dialogContextProvider = dialogContextProvider;
        
        RegisterViews();
    }

    public override object Create(object viewModel)
    {
        var control = base.Create(viewModel);
        if (control is Window window)
        {
            _dialogContextProvider.DialogContext = new DialogContext(window.GetHashCode(), null);
        }

        return control;
    }

    public void RegisterViews()
    {
        ....
    }
}

And create a new scope when you start a new window:

serviceCollection.AddScoped<IDialogContextProvider, DialogContextProvider>();
....
public class YourViewModel : ViewModelBase, IDialogContextOwner
{
    private readonly IServiceProvider _serviceProvider;
    private readonly IDialogService _dialogService;
    private readonly IDialogContextProvider _dialogContextProvider;
    
    //Constructor is omited
    
    public DialogContext? DialogContext
    {
        get => _dialogContextProvider.DialogContext;
        set
        {
            if(value!=null)
                _dialogContextProvider.DialogContext = value;
        }
    }
    
    public async Task SomeCommand()
    {
        var scope = _serviceProvider.CreateScope();
        var vm = scope.ServiceProvider.GetRequiredService<YourDialogViewModel>();
        await _windowDialogService.ShowDialogAsync(this, vm);
    }
}

Both window and overlay dialog will be shown in the right window.

To find a full sample, see the MvvmDialogs.Avalonia.Ursa.Demo project.