UWP C# Store and Load Serial Device Information

Question

I would like to find out how to store & load serial deviceinformation. I have referred to UWP Serial Sample and tested the serial to RS485.

I am using a FTDI USB to UART-RS485 converter on raspberry pi running Windows IoT Core. I do not intend to use the onboard UART. So I am wondering if I am able to save the SerialPort.id to Windows.Storage.ApplicationDataContainer and load it when the application starts to ensure it connects to the correct SerialPort.

1. How do I get the SerialPort readable name like USB-RS485-Cable etc . becasue when i use SerialComsDisplay.Text = listOfDevices[SerialDeviceList.SelectedIndex].Id.ToString(); it read the ID which are in code.

2. It doesn't seems to load the correct SerialPort after i load it.

Please help. Thanks.

Saving the SerialPort to container

    private void SaveSerialConfig_Click(object sender, RoutedEventArgs e)
    {
        Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;

        localSettings.Values["SerialDevice"] = listOfDevices[SerialDeviceList.SelectedIndex].Name;
        SerialComsDisplay.Text = listOfDevices[SerialDeviceList.SelectedIndex].Id.ToString();
    }

Startup code to initialize the SerialPort when app starts

private async void ListAvailablePorts()
    {
        try
        {
            string aqs = SerialDevice.GetDeviceSelector();
            var dis = await DeviceInformation.FindAllAsync(aqs);

            SerialComsDisplay.Text = "Select a device and connect";

            for (int i = 0; i < dis.Count; i++)
            {
                listOfDevices.Add(dis[i]);
            }

            DeviceListSource.Source = listOfDevices;
            SerialDeviceList.SelectedIndex = 0;
        }
        catch (Exception ex)
        {
            SerialComsDisplay.Text = ex.Message;
        }

        connectCommPort();
    }


private async void connectCommPort()
    {
        var selection = SerialDeviceList.SelectedItems;
        DeviceInformation entry;

        if (selection.Count <= 0)
        {
            SerialComsDisplay.Text = "\n Select a device and connect";
            return;
        }

        Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
        if (localSettings.Values["SerialDevice"] != null)
        {
            var device = localSettings.Values["SerialDevice"];
            SerialComsDisplay.Text = device.ToString();
            entry = (DeviceInformation)device;
        }
        else
        {
            entry = (DeviceInformation)selection[0];
        }

        try
        {
            serialPort = await SerialDevice.FromIdAsync(entry.Id);
            if (serialPort == null) return;

            // Configure serial settings
            serialPort.WriteTimeout = TimeSpan.FromMilliseconds(0);//10 //1000
            serialPort.ReadTimeout = TimeSpan.FromMilliseconds(50);//100 //1000
            //serialPort.BaudRate = 9600;
            serialPort.BaudRate = 4800;
            serialPort.Parity = SerialParity.None;
            serialPort.StopBits = SerialStopBitCount.One;
            serialPort.DataBits = 8;
            serialPort.Handshake = SerialHandshake.None;

            // Display configured settings
            SerialComsDisplay.Text = "Serial port configured successfully: ";
            SerialComsDisplay.Text += serialPort.BaudRate + "-";
            SerialComsDisplay.Text += serialPort.DataBits + "-";
            SerialComsDisplay.Text += serialPort.Parity.ToString() + "-";
            SerialComsDisplay.Text += serialPort.StopBits;

            // Set the RcvdText field to invoke the TextChanged callback
            // The callback launches an async Read task to wait for data
            SerialComsDisplay.Text = "Waiting for data...";

            // Create cancellation token object to close I/O operations when closing the device
            ReadCancellationTokenSource = new CancellationTokenSource();

            if (serialPort != null)
            {
                dataWriteObject = new DataWriter(serialPort.OutputStream);
                dataReaderObject = new DataReader(serialPort.InputStream);
            }

            Listen();

            startPollTimer();
        }
        catch (Exception ex)
        {
            SerialComsDisplay.Text = ex.Message;
        }
    }

Answer 1

1.How do I get the SerialPort readable name like USB-RS485-Cable etc . becasue when i use SerialComsDisplay.Text = listOfDevices[SerialDeviceList.SelectedIndex].Id.ToString(); it read the ID which are in code.

The property DeviceInformation.Name shows the readable name of the device.Please note that this property should only be used for display purposes only and not for finding a device because the Name can change due to localization or a user assigning a name.

2.It doesn't seems to load the correct SerialPort after i load it.

I reviewed your code, found out that you stored the name of DeviceInformation as SerialDevice but not a object of DeviceInformation,

localSettings.Values["SerialDevice"] = listOfDevices[SerialDeviceList.SelectedIndex].Name;

however when you loaded the setting, you parse the string to object.

var device = localSettings.Values["SerialDevice"];
SerialComsDisplay.Text = device.ToString();
entry = (DeviceInformation)device;

UPDATE:

private async void connectCommPort()
{
    var selection = SerialDeviceList.SelectedItems;
    string deviceId;

    if (selection.Count <= 0)
    {
        SerialComsDisplay.Text = "\n Select a device and connect";
        return;
    }

    Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
    Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
    if (localSettings.Values["SerialDevice"] != null)
    {
        var deviceId = localSettings.Values["SerialDevice"];
        SerialComsDisplay.Text = deviceId;
    }
    else
    {
        deviceId = （(DeviceInformation)selection[0]).Id;
    }

    try
    {
        serialPort = await SerialDevice.FromIdAsync(deviceId );
        if (serialPort == null) return;

        // Configure serial settings
        serialPort.WriteTimeout = TimeSpan.FromMilliseconds(0);//10 //1000
        serialPort.ReadTimeout = TimeSpan.FromMilliseconds(50);//100 //1000
        //serialPort.BaudRate = 9600;
        serialPort.BaudRate = 4800;
        serialPort.Parity = SerialParity.None;
        serialPort.StopBits = SerialStopBitCount.One;
        serialPort.DataBits = 8;
        serialPort.Handshake = SerialHandshake.None;

        // Display configured settings
        SerialComsDisplay.Text = "Serial port configured successfully: ";
        SerialComsDisplay.Text += serialPort.BaudRate + "-";
        SerialComsDisplay.Text += serialPort.DataBits + "-";
        SerialComsDisplay.Text += serialPort.Parity.ToString() + "-";
        SerialComsDisplay.Text += serialPort.StopBits;

        // Set the RcvdText field to invoke the TextChanged callback
        // The callback launches an async Read task to wait for data
        SerialComsDisplay.Text = "Waiting for data...";

        // Create cancellation token object to close I/O operations when closing the device
        ReadCancellationTokenSource = new CancellationTokenSource();

        if (serialPort != null)
        {
            dataWriteObject = new DataWriter(serialPort.OutputStream);
            dataReaderObject = new DataReader(serialPort.InputStream);
        }

        Listen();

        startPollTimer();
    }
    catch (Exception ex)
    {
        SerialComsDisplay.Text = ex.Message;
    }
}