Orleans具备非常简单的异常传递机制，Grain或Placement注解逻辑抛异常，可以直接传递到客户端，测试代码如下：

首先在客户端、Silo服务程序的Main方法增加ThreadException事件处理函数，避免未处理异常导致进程闪退。

        static void Main()
        {
            // To customize application configuration such as set high DPI settings or default font,
            // see https://aka.ms/applicationconfiguration.
            Application.ThreadException += (sender, ex) =>
            {
                using (var dlg = new ThreadExceptionDialog(ex.Exception))
                {
                    dlg.ShowDialog();
                }
            };
            ApplicationConfiguration.Initialize();
            System.Windows.Forms.Application.Run(new Form1());
        }

Placement逻辑抛异常代码如下，如获取id为camera3的Grain远程实例则抛异常：

        public Task<SiloAddress> OnAddActivation(PlacementStrategy strategy, PlacementTarget target, IPlacementContext context)
        {
            var grainID = target.GrainIdentity.Key.ToString();
            var silos = context.GetCompatibleSilos(target).ToArray();
            SiloAddress siloAddress = silos.First();
            if (grainID == "user1" || grainID == "camera1")
                siloAddress = silos?.FirstOrDefault(x => x.Endpoint.Port == 11111) ?? siloAddress;
            else if (grainID == "user2" || grainID == "camera2")
                siloAddress = silos?.FirstOrDefault(x => x.Endpoint.Port == 11112) ?? siloAddress;
            else if (grainID == "camera3")
                throw new Exception("非法的graid id");
            return Task.FromResult(siloAddress);
        }

Grain内函数抛异常代码如下：

        public async Task RunAnExceptionMethod()
        {
            throw new NotImplementedException("这是一个故意在服务端抛出异常的方法");
        }

客户端调用后报错如下截图：

总结：Grain方法抛异常，不会影响服务端，仅在客户端执行线程异常事件处理函数（本例弹窗提示），服务端的线程异常事件处理函数没有执行（但必须有，否则服务端闪退）。