Last post Nov 19, 2019 09:09 AM by ernesto_gf
Nov 18, 2019 11:39 AM|ernesto_gf|LINK
Hi there! I´m having problems to plot data on a web chart when I receive it from M2MQTT library (client_MqttMsgPublishReceived method) which run in a different thread. I have used the same library for a desktop application, and in these case using Dispatcher.
Invoke I have solved this problem. I am new programming web application so have been so difficult to solve this ploblem. When I debug the code the messages are being received OK, so the problem is when trying to plot it in the chart.
Thanks in advance for your help!
Nov 19, 2019 03:08 AM|Yang Shen|LINK
When I debug the code the messages are being received OK, so the problem is when trying to plot it in the chart.
We could use the code where you're trying to plot the chart. Also, please provide sample data which you want to plot in the chart which you said received OK when you debugged it.
Nov 19, 2019 08:35 AM|ernesto_gf|LINK
Hi Yang Shen,
I have a method which plot the data taking data from a string. When I use this method in the Page_Load method it works but when calling it from the received data method I obtain a NullObjectReference error refered to the Chart. The received data method run
in a different thread and I think this is the problem. For a desktop application this problem is easy to solve by using Dispatcher.Invoke but I don´t know how to develop something similar on a web application.
Nov 19, 2019 09:09 AM|ernesto_gf|LINK
These is the received data method from which the chart is not accesible and give NullReferenceException
public void client_MqttMsgPublishReceived(object sender, MqttMsgPublishEventArgs e)
ReceivedMessage = Encoding.UTF8.GetString(e.Message);