/// <summary>
/// Perform functions in form from a different thread. See AccessFormMarshal.
/// </summary>
/// <remarks>
/// Based on methods used by Jan Axelson in Serial Port Complete 2nd edition. I break it out a little further
/// as I handle exceptions seperately.
/// </remarks>
/// <param name="userInterfaceAction">Enum that indicates which action to perform</param>
/// <param name="comPortData">Com Port data being returned if applicable</param>
private void AccessForm(ComPort.ComPortEvent userInterfaceAction, string comPortData)
{
switch (userInterfaceAction)
{
case ComPort.ComPortEvent.ReturnNewData:
//Retrieve new com port data.
ProcessReloadData(comPortData);
break;
case ComPort.ComPortEvent.ReportStatus:
//Display ComPort status.
comPortStatusLabel.Text = comPortData;
break;
case ComPort.ComPortEvent.ReportException:
//Exception occured in ComPort.
MessageBox.Show(comPortData, "Exception Occurred", MessageBoxButtons.OK, MessageBoxIcon.Error);
break;
case ComPort.ComPortEvent.ReportSerialError:
//Serial error occured in ComPort.
comPortErrorsTextBox.AppendText(DateTime.Now.ToString() + " - " + comPortData + Environment.NewLine);
break;
}
}
/// <summary>
/// Enables accessing the form from another thread. The parameters match those of AccessForm.
/// </summary>
/// <remarks>
/// Based on methods used by Jan Axelson in Serial Port Complete 2nd edition, except I use
/// BeginInvoke rather than Invoke, to avoid the deadlock issue.
/// </remarks>
/// <param name="userInterfaceAction">Enum that indicates which action to perform</param>
/// <param name="comPortData">Com Port data being returned if applicable</param>
private void AccessFormMarshal(ComPort.ComPortEvent userInterfaceAction, string comPortData)
{
AccessFormMarshalDelegate accessFormMarshalDelegate = new AccessFormMarshalDelegate(AccessForm);
object[] args = { userInterfaceAction, comPortData };
//Call AccessForm, passing the parameters in args. I use BeginInvoke, after reading several sources indicating
//it should be used to avoid a deadlock when the port is closed. Initially I saw it in Alex F.'s comments here:
//http://forums.codeguru.com/showthread.php?516248-RESOLVED-Serial-port-hangs-on-form-close, more explanation here:
//http://blogs.msdn.com/b/bclteam/archive/2006/10/10/top-5-serialport-tips-_5b00_kim-hamilton_5d00_.aspx. I'm not
//sure if there are any downsides yet, but it fixed the deadlock for me, and everything still seems to work okay.
base.BeginInvoke(accessFormMarshalDelegate, args);
}
