Solution:

Create a new class dialogserviceextend, and then register it in the

    public class DialogServiceExtend : DialogService
    {
        public DialogServiceExtend(IContainerExtension containerExtension) : base(containerExtension)
        {
        }

        protected override void ConfigureDialogWindowEvents(IDialogWindow dialogWindow, Action<IDialogResult> callback)
        {
            Action<IDialogResult> requestCloseHandler = null;
            requestCloseHandler = (o) =>
            {
                dialogWindow.Result = o;
                dialogWindow.Close();
            };

            RoutedEventHandler loadedHandler = null;
            loadedHandler = (o, e) =>
            {
                dialogWindow.Loaded -= loadedHandler;
                GetDialogViewModel(dialogWindow).RequestClose += requestCloseHandler;
            };
            dialogWindow.Loaded += loadedHandler;

            CancelEventHandler closingHandler = null;
            closingHandler = (o, e) =>
            {
                if (!GetDialogViewModel(dialogWindow).CanCloseDialog())
                {
                    callback?.Invoke(dialogWindow.Result);
                    e.Cancel = true;
                }
            };
            dialogWindow.Closing += closingHandler;

            EventHandler closedHandler = null;
            closedHandler = (o, e) =>
            {
                dialogWindow.Closed -= closedHandler;
                dialogWindow.Closing -= closingHandler;
                GetDialogViewModel(dialogWindow).RequestClose -= requestCloseHandler;

                GetDialogViewModel(dialogWindow).OnDialogClosed();

                if (dialogWindow.Result == null)
                    dialogWindow.Result = new DialogResult();

                callback?.Invoke(dialogWindow.Result);

                dialogWindow.DataContext = null;
                dialogWindow.Content = null;
            };
            dialogWindow.Closed += closedHandler;
        }

        private IDialogAware GetDialogViewModel(IDialogWindow dialogWindow)
        {
            return (IDialogAware)dialogWindow.DataContext;
        }
    }

register

    protected override void RegisterTypes(IContainerRegistry containerRegistry)
    {
        containerRegistry.RegisterSingleton<IDialogService, DialogServiceExtend>();
    }

Then you can find that the callback can take effect