Question

我有一个类似于下面的ASP.NET MVC Controller方法：

    public JsonResult GenerateNotifications()
    {
        Task.Factory.StartNew(() => MyService.GenerateNotifications());
        return Json(new { success = true }, JsonRequestBehavior.AllowGet);
    }

我的服务方法如下所示：

    public async void GenerateNotifications()
    {
        NotificationHubClient hub = NotificationHubClient.CreateClientFromConnectionString(AppHelper.AzureNotificationHubConnectionString, "myhub");

        for (int i = 0; i < 10; i++)
        {
            var notification = new
            {
                aps = new
                {
                    alert = string.Format("Awesome Notification {0}", i),
                    sound = "default"
                }
            };

            string notificationJSON = JsonConvert.SerializeObject(notification);
            NotificationOutcome result = await hub.SendAppleNativeNotificationAsync(notificationJSON, "mytag");
        }
    }

我遇到的问题是，我应该收到的10个通知中，我通常只收到5-6个通知。

我处理async电话的方式有问题吗？

我是否应该以与控制器不同的方式生成通知？

Answer 1

由于GenerateNotification方法为async void，您可能会收到一些被吞下的异常。您应该返回Task并确保await方法，以便观察和重新抛出异常。

完成后，您可以Task.Factory.StartNew(() => MyService.GenerateNotifications())而不是await MyService.GenerateNotifications()。有关使用async/await

的一些注意事项，请参阅Best Practices in Asynchronous Programming

我会将您的代码更改为：

    public async Task<JsonResult> GenerateNotifications()
    {
        await MyService.GenerateNotifications();
        return Json(new { success = true }, JsonRequestBehavior.AllowGet);
    }

    public async Task GenerateNotifications()
    {
        NotificationHubClient hub = NotificationHubClient.CreateClientFromConnectionString(AppHelper.AzureNotificationHubConnectionString, "myhub");

        for (int i = 0; i < 10; i++)
        {
            var notification = new
            {
                aps = new
                {
                    alert = string.Format("Awesome Notification {0}", i),
                    sound = "default"
                }
            };

            string notificationJSON = JsonConvert.SerializeObject(notification);
            NotificationOutcome result = await hub.SendAppleNativeNotificationAsync(notificationJSON, "mytag");
        }
    }

目前，您还会连续发送通知。您可以将生成的任务添加到列表中，然后使用await Task.WhenAll await完成它们，将它们并行发送出来。

public async Task GenerateNotifications()
{
    NotificationHubClient hub = NotificationHubClient.CreateClientFromConnectionString(AppHelper.AzureNotificationHubConnectionString, "myhub");

    List<Task<NotificationOutcome>> notificaitonTasks = new List<Task<NotificationOutcome>>();

    for (int i = 0; i < 10; i++)
    {
        var notification = new
        {
            aps = new
            {
                alert = string.Format("Awesome Notification {0}", i),
                sound = "default"
            }
        };

        string notificationJSON = JsonConvert.SerializeObject(notification);
        notificaitonTasks.Add(hub.SendAppleNativeNotificationAsync(notificationJSON, "mytag"));
    }

    await Task.WhenAll(notificaitonTasks);
}

Windows Azure Service Bus通知中心仅接收通知部分

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