我应该如何使用Avalonia(ReactiveUI)使命令具有可执行性

Question

我正试图根据以下指南实现控制ReactiveUI命令的可执行性：指南
但我遇到了一个例外："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;
}
}

Answer 1

在this.WhenAnyValue中，选择器表达式指向字段而不是属性。将其更改为CCD_ 2。