How can I send a batch of messages to an Azure EventHub? (C# WinForm and .NET 5.0)

I am building a telemetry simulator to send messages to an Azure EventHub (WinForm, .NET 5.0).

I use backgroundworkers for each telemetry device, the code below is the DoWork method of one of the devices. The app works fine when I output the messages to the console.

The problem occurs when I add the (commented out) EventHub code shown in the while loop below. There are two issues:

1. Backgroundworker.ReportProgress fails with: System.InvalidOperationException: 'This operation has already had OperationCompleted called on it and further calls are illegal.'

2. I also can no longer cancel the process (i.e. truckWorker.CancellationPending is always false)

If I uncomment the EventHub code, and comment out truckWorker.ReportProgress(i++), the app works and sends messages to the EventHub. Problem is I still can't cancel the operation and of course I loose my progress indicator.

private async void SendTruckMsg(object sender, DoWorkEventArgs e)  {      EventHubProducerClient evClient = (EventHubProducerClient)e.Argument;      List<TruckTelemetry> collection = virtualThingsController.GetTruckTelemetry();      int interval = virtualThingsController.GetTruckTelemetryInterval();      int i = 0; // count messages sent         while (!truckWorker.CancellationPending)  // ===> can't cancel operation anymore      {          //using var eventBatch = await evClient.CreateBatchAsync(); // create batch            foreach (TruckTelemetry truckTelemetry in collection)          {              truckTelemetry.Timestamp = DateTime.Now;              string output = JsonConvert.SerializeObject(truckTelemetry);                            //eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes(output))); // add to batch          }            //await evClient.SendAsync(eventBatch); // send the batch            truckWorker.ReportProgress(i++);            Thread.Sleep(interval);      }  }  

Sending messages could be synchronous but there is no simple 'send' method for the EventHubProducerClient.

Appreciate any help, thanks.

https://stackoverflow.com/questions/67041273/how-can-i-send-a-batch-of-messages-to-an-azure-eventhub-c-winform-and-net-5 April 11, 2021 at 11:46AM