C#和Caliburn-救援属性和协作

我想我找到了一个救援属性被破坏的情况。或者我用错了共同程序。

我有一个这样的视图模型:

[Rescue("Rescue")]
class MyViewModel
{
    //... left out some bus-logic code here ...

    public void Login()
    {
        yield return Show.Busy();

        //the following line will also cause the problem, just like AsyncResult
        //yield return Show.MessageBox("Test");

        yield return new AsyncResult(() => _server.Login());

        //throw new Exception("Aww, snap!");

        yield return Show.NotBusy();
    }

    public void Rescue(Exception exc)
    {
        //Show a messagebox or something
    }
}

AsyncResult的实现方式如下:

using Exec = Caliburn.PresentationFramework.Invocation.Execute;

    public class AsyncResult : IResult
    {
        private readonly Action _function;

        public AsyncResult(Action function)
        {
            _function = function;
        }

        public void Execute(ResultExecutionContext context)
        {
            Exec.OnBackgroundThread(delegate
            {
                try
                {
                    _function();
                }
                catch (Exception exc)
                {
                    Exec.OnUIThread(() => Completed(this, new ResultCompletionEventArgs { Error = exc, WasCancelled = true }));
                    return;
                }
                Exec.OnUIThread(() => Completed(this, new ResultCompletionEventArgs()));
            });
        }

        public event EventHandler<ResultCompletionEventArgs> Completed = delegate { };
    }

如果我在上面的ViewModel中取消注释异常,Rescue将无法处理该异常。

这是Caliburn中的一个bug,还是AsyncResult实现错误?

如果将异常放在yield之前以返回AsyncResult,那么Rescue工作得很好。如果抛出异常 异步线程,救援仍然有效!

编辑:您也可以使用Show.MessageBox而不是AsyncResult来重现相同的问题。