我应该如何使用 Avalonia(ReactiveUI) 控制命令的可执行性？

如何解决我应该如何使用 Avalonia(ReactiveUI) 控制命令的可执行性？

我正在尝试根据本指南实现控制 ReactiveUI 命令的可执行性：guide。
但我收到一个异常：“由于对象的当前状态，操作无效。”
我该如何解决？
我的代码示例：

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;
    }

}

解决方法

在 this.WhenAnyValue 中，您的选择器表达式指向字段而不是属性。将其更改为 this.WhenAnyValue(x => x.Path,x => x.Name,(name,path) => !string.IsNullOrWhiteSpace(name) && !string.IsNullOrWhiteSpace(path));。