5 replies to this topic

[emence]

Hi!

I'm trying to use SerialPort as a parameter for my other classes constructor:

serial1 = new SerialPort(SerialPorts.COM1, Constants.baud_cam, Parity.None, 8, StopBits.One);
serial1.DataReceived += new SerialDataReceivedEventHandler(camera_DataReceived);
serial1.Open();
Ucamttl camera = new Ucamttl(serial1);

Ucamttl class:

SerialPort serial;

    public Ucamttl(SerialPort sp)
    {
        serial = sp;
    }

I can't seem to use the serialPort in my Ucamttl class. It works well in the main routine though.
The error occurs when the ucamttl class tries to write to the serial ( serial.Write(_command,0,Constants.CMD_SIZE); )

    #### Exception System.NullReferenceException - CLR_E_NULL_REFERENCE (1) ####
    #### Message: 
    #### Thermocam.Program::SyncCam [IP: 0007] ####
    #### Thermocam.Program::Main [IP: 008d] ####

Since I'm a noob there are a lot of questions..
- In which class do i need to open the port?
- In which class do i need to implement the event handlers?
- and if, then how, and why?

Thanks for helping!

[Stefan]

Hi and welcome to the forums, Could it be that the garbage collector does this? Could you add a Thread.Sleep(Timeout.Infinite); at the bottom of your main method?

[CW2]

Do you have by any chance another instance of "Ucamttl camera" declared above your Main method? If not, could you please post the whole source code, as the above snippets do not show what is happening inside SyncCam?

[Chris Walker]

As Stefan and CW2 alluled, the most likely scenario is that your SerialPort is not being passed properly...or is getting cleaned up by the garbage collector. If you can post a bit more of your code, we can help diagnose a bit deeper. Chris

[emence]

Do you have by any chance another instance of "Ucamttl camera" declared above your Main method?

Yes. exactly!

Of course I used a static Object! And declared a new one with the same name when calling the constructor!
Ahhh... such a simple mistake! Everything is working properly now!

Thanks for Your time!

[Chris Walker]

Yes. exactly!

Of course I used a static Object! And declared a new one with the same name when calling the constructor!
Ahhh... such a simple mistake! Everything is working properly now!

Good catch, CW2!

Glad it's working for you, emence.

Chris