CODEWITHSUNDEEP
c#reactiveuiavaloniaui
Pariah
Pariah

Reputation: 55

How should I make a controlling executability of command using Avalonia(ReactiveUI)?

I am trying to implement controlling executability of ReactiveUI command according to this guide: guide.
But I am getting an exception: "Operation is not valid due to the current state of the object."
How should I fix that?
My code sample:

public class CreateBookViewModel : ViewModelBase
{
    IObservable<bool> canExecuteCreateBookCommand;
    private string? name;
    private string? path;
    public ReactiveCommand<Unit, Unit> ChangePathCommand { get; }
    public ReactiveCommand<Unit, EditBookViewModel?> CreateBookCommand { get; }


    public string? Name 
    {
        get => name;
        set => this.RaiseAndSetIfChanged(ref name, value);
    }
    public string? Path
    {
        get => path;
        set => this.RaiseAndSetIfChanged(ref path, value);
    }

    public CreateBookViewModel()
    {
        canExecuteCreateBookCommand = this.WhenAnyValue(x => x.path, x => x.name, (name, path) =>
            !string.IsNullOrWhiteSpace(name) && !string.IsNullOrWhiteSpace(path));
        ChangePathCommand = ReactiveCommand.CreateFromTask(RunChangePath);
        CreateBookCommand = ReactiveCommand.Create(RunCreateBook, canExecuteCreateBookCommand);
    }

    private async Task RunChangePath()
    {
       var dialog = new OpenFolderDialog();
       Path = await dialog.ShowAsync(CreateBookWindow.Instance);
    }

    private  EditBookViewModel? RunCreateBook()
    {
        if(name!= null && path!= null)
        {
            EditBookViewModel book = new EditBookViewModel(name, path);
            return book;
        }
        return null;
    }

}

Upvotes: 2

Views: 331

Answers (1)

lipharDYT
lipharDYT

Reputation: 36

In this.WhenAnyValue your selector expression is pointing towards a field instead of a property. Change it to this.WhenAnyValue(x => x.Path, x => x.Name, (name, path) => !string.IsNullOrWhiteSpace(name) && !string.IsNullOrWhiteSpace(path));.

Upvotes: 1

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