Avalonia UI 的 OpenFileDialog 和 SaveFileDialog - 如何检测被单击的取消按钮

Avalonia UI's OpenFileDialog and SaveFileDialog - How to detect a cancel button being clicked

使用此处打开 SaveFileDialog 的代码,我如何检测用户是否按下取消?

     SaveFileDialog SaveFileBox = new SaveFileDialog();
     SaveFileBox.Title = "Save Document As...";
     SaveFileBox.InitialFileName = Path.GetFullPath(DocumentFileName);
     SaveFileBox.Directory = workdir;
     List<FileDialogFilter> Filters = new List<FileDialogFilter>();
     FileDialogFilter filter = new FileDialogFilter();
     List<string> extension = new List<string>();
     extension.Add("doc");
     filter.Extensions = extension;
     filter.Name = "Document Files";
     Filters.Add(filter);
     SaveFileBox.Filters = Filters;

     SaveFileBox.DefaultExtension = "doc";

     SettingsFileName = await SaveFileBox.ShowAsync(this);

提前致谢!!

ShowAsync 的 return 值将为 null 或空数组。