用户代码未处理的异常

Question

I have a member of a library being declared on the main page of my app:

private OpticalReaderLib.OpticalReaderTask _task = new OpticalReaderLib.OpticalReaderTask();

It works fine until I want to navigate back to this page at a different time. It brings up the error "An exception of type 'System.Exception' occurred in OpticalReaderLib.DLL but was not handled in user code".

Does anyone know why this is happening?

Thanks.

Answer 1

System.Exception is the base class for all Exceptions, so this is a very generic error message.

You could try logging more detail (eg exception.Message or exception.InnerException) about the exception that is thrown as part of your investigation. (via a try-catch statement).

It looks like you're initialising a field, where is this code being executed?

---

Update due to comment As a temporary solution to discover the exception error.

    private OpticalReaderLib.OpticalReaderTask _tempTask;
    private OpticalReaderLib.OpticalReaderTask _task
    {
        get
        {
            //code to debug the error that is occuring
            try
            {
                if (_tempTask == null)
                    _tempTask = new OpticalReaderLib.OpticalReaderTask();
                else
                    return _tempTask;
            }
            catch (Exception exception)
            {
                //Log the exception detail here 
            }
        } 
    }

Answer 2

  protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
  {
    if (_task != null) 
    { 
      _task.Completed -= OpticalReaderTask_Completed; 
      _task.Dispose(); 
      _task = null; 
    } 
    base.OnBackKeyPress(e);
  }