Question

我目前正在尝试为我的IoT学校项目开发简单的Web应用程序。至于现在它应该只从我的Raspberry调用直接方法。我正在使用Azure SDK for C＃。

这就是代码的样子：

控制器：

    public ActionResult changeState(int? id, bool enable)
    {
        string conn_str = (from u in db.Users join h in db.Hubs on
                u.Hub.HubId equals h.HubId
                where u.UserName == User.Identity.Name select h.connection_str).First();

        Cloud2Device c2d = new Cloud2Device(conn_str);

        if (id == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        Rp rp = db.Rps.SingleOrDefault(r => r.RpId == id);
        if (rp == null)
        {
            return HttpNotFound();
        }
        //IoT stuff
        try
        {
           c2d.EnableRaspberry("myDeviceId").Wait();
        }
        catch(Exception ex)
        {
           //do something
        }
        rp.is_enabled = enable;
        db.SaveChanges();
        return RedirectToAction("Index");
    }

IoT utils：

public class Cloud2Device
{
    private ServiceClient s_serviceClient;

    public Cloud2Device(string conn_str)
    {
        s_serviceClient = ServiceClient.CreateFromConnectionString(conn_str);
    }

    public async Task EnableRaspberry(string deviceId)
    {
        var methodInvocation = new CloudToDeviceMethod("EnableRaspberry") { ResponseTimeout = TimeSpan.FromSeconds(2) };

         var response = await s_serviceClient.InvokeDeviceMethodAsync(deviceId, methodInvocation);
        Debug.WriteLine(response.GetPayloadAsJson());
    }
}

问题是从调试输出我可以看到异常Microsoft.Azure.Devices.Common.Exceptions.DeviceNotFoundException 被抛出然后它不被try-catch块处理。

console output

    Application Insights Telemetry (unconfigured): "name":"Microsoft.ApplicationInsights.Dev.RemoteDependency","time":"2018-05-29T12:04:59.4748528Z","tags":{"ai.internal.sdkVersion":"rddf:2.2.0-738","ai.internal.nodeName":"5CG6455YJ4.ericsson.se","ai.cloud.roleInstance":"5CG6455YJ4.ericsson.se"},"data":{"baseType":"RemoteDependencyData","baseData":{"ver":2,"name":"/twins/myDeviceId/methods","id":"8/ZMgqG4iNc=","data":"https://utiliothub.azure-devices.net/twins/myDeviceId/methods?api-version=2017-10-15","duration":"00:00:01.2380000","resultCode":"404","success":false,"type":"Http","target":"utiliothub.azure-devices.net","properties":{"DeveloperMode":"true"}}}}
    Exception thrown:'Microsoft.Azure.Devices.Common.Exceptions.DeviceNotFoundException' in Microsoft.Azure.Devices.dll
    Exception thrown:'Microsoft.Azure.Devices.Common.Exceptions.DeviceNotFoundException' in mscorlib.dll
    The thread 0x3834 has exited with code 0 (0x0).

任何人都可以建议我如何在我的应用程序中捕获并处理此异常？在此先感谢您的回答。

Answer 1

我不确定错误输出实际上是抛出代码的异常。它可能只是日志记录的ApplicationInsights。 但是，我认为代码因调用.local.com并阻止异步方法的返回而被冻结。

使控制器方法返回类型Wait，使该方法Task<ActionResult>，然后使用async来调用该方法。

看看这样做是否会导致异常（或成功）。

无法在ASP.NET MVC中捕获异常

1 个答案: