在官方範例中,一頁式的程式碼不易重用，便著手把Serial Port通訊部分抽取出一個獨立的class
卻怎麼無法順利讀取到資料，花了不少時間一測再測終於
UWP SerialPort 通信這一行不加，怎麼都收不到資料．．．．
在官方範例中
/// <summary>
/// comPortInput_Click: Action to take when 'Connect' button is clicked
/// - Get the selected device index and use Id to create the SerialDevice object
/// - Configure default settings for the serial port
/// - Create the ReadCancellationTokenSource token
/// - Start listening on the serial port input
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private async void comPortInput_Click(object sender, RoutedEventArgs e)
{
var selection = ConnectDevices.SelectedItems;
if (selection.Count <= 0)
{
status.Text = "Select a device and connect";
return;
}
DeviceInformation entry = (DeviceInformation)selection[0];
try
{
serialPort = await SerialDevice.FromIdAsync(entry.Id);
// Disable the 'Connect' button
comPortInput.IsEnabled = false;
// Configure serial settings
serialPort.WriteTimeout = TimeSpan.FromMilliseconds(100);
serialPort.ReadTimeout = TimeSpan.FromMilliseconds(100);
serialPort.BaudRate = 19200;
serialPort.Parity = SerialParity.None;
serialPort.StopBits = SerialStopBitCount.One;
serialPort.DataBits = 8;
serialPort.Handshake = SerialHandshake.None;
serialPort.IsDataTerminalReadyEnabled = true;
// Display configured settings
status.Text = "Serial port configured successfully: ";
status.Text += serialPort.BaudRate + "-";
status.Text += serialPort.DataBits + "-";
status.Text += serialPort.Parity.ToString() + "-";
status.Text += serialPort.StopBits;
// Set the RcvdText field to invoke the TextChanged callback
// The callback launches an async Read task to wait for data
rcvdText.Text = "Waiting for data...";
// Create cancellation token object to close I/O operations when closing the device
ReadCancellationTokenSource = new CancellationTokenSource();
// Enable 'WRITE' button to allow sending data
sendTextButton.IsEnabled = true;
Listen();
}
catch (Exception ex)
{
status.Text = ex.Message;
comPortInput.IsEnabled = true;
sendTextButton.IsEnabled = false;
}
}
其中的這段只是把資訊顯示在畫面上，抽取成獨立的class完全不需要這一段
// Display configured settings
status.Text = "Serial port configured successfully: ";
status.Text += serialPort.BaudRate + "-";
status.Text += serialPort.DataBits + "-";
status.Text += serialPort.Parity.ToString() + "-";
status.Text += serialPort.StopBits;
但把它移除後，程式就再也無法正常接收資料，很不合理，
幾經波折後終於發現是什麼問題了
當設定完serialPort.BaudRate後，必須再把它讀出來一次就會正常了
例. uint baudRate = serialPort.BaudRate;
雖然找到問題點了，但目前還是不知道為什麼會有這樣的設計，我想它就是一個莫名奇妙的bug
