Windows通用应用程序串行端口将不会打开，SerialDevice.FromIdAsync始终为空

我正在尝试使用Windows通用应用程序中的串行端口。 我一直在使用微软的Serial Sample应用程序作为模板，但是我遇到了一个相当奇怪的问题。

var dis = await DeviceInformation.FindAllAsync(SerialDevice.GetDeviceSelectorFromUsbVidPid(0x04D8, 0x000A)); var sp = await SerialDevice.FromIdAsync(dis[0].Id); 

这是一个失败的片段。 它与原始样本稍有不同，因为它与特定供应商连接到第一个设备。 现在，如果我把这个代码片段放到Microsoft生成的示例应用程序中，串口就会打开，并且一切都很好。 但是，当我把这个代码移到我自​​己的项目中时，它总是从方法中返回null 。

这里是从微软示例完整的MainPage.xaml.cs与我的aleures： 这工程！

 // Copyright (c) Microsoft. All rights reserved. using System; using System.Collections.ObjectModel; using System.Diagnostics; using System.Linq; using Windows.UI.Xaml; using Windows.UI.Xaml.Controls; using Windows.Devices.Enumeration; using Windows.Devices.SerialCommunication; using Windows.Storage.Streams; using System.Threading; using System.Threading.Tasks; namespace SerialSample { public sealed partial class MainPage : Page { /// <summary> /// Private variables /// </summary> private SerialDevice serialPort = null; DataWriter dataWriteObject = null; DataReader dataReaderObject = null; private ObservableCollection<DeviceInformation> listOfDevices; private CancellationTokenSource ReadCancellationTokenSource; public MainPage() { this.InitializeComponent(); comPortInput.IsEnabled = false; sendTextButton.IsEnabled = false; listOfDevices = new ObservableCollection<DeviceInformation>(); ListAvailablePorts(); } /// <summary> /// ListAvailablePorts /// - Use SerialDevice.GetDeviceSelector to enumerate all serial devices /// - Attaches the DeviceInformation to the ListBox source so that DeviceIds are displayed /// </summary> private async void ListAvailablePorts() { try { string aqs = SerialDevice.GetDeviceSelector(); var dis = await DeviceInformation.FindAllAsync(SerialDevice.GetDeviceSelectorFromUsbVidPid(0x04D8, 0x000A)); serialPort = await SerialDevice.FromIdAsync(dis[0].Id); status.Text = "Select a device and connect"; for (int i = 0; i < dis.Count; i++) { listOfDevices.Add(dis[i]); } DeviceListSource.Source = listOfDevices; comPortInput.IsEnabled = true; ConnectDevices.SelectedIndex = -1; try { // Disable the 'Connect' button comPortInput.IsEnabled = false; // Configure serial settings serialPort.WriteTimeout = TimeSpan.FromMilliseconds(1000); serialPort.ReadTimeout = TimeSpan.FromMilliseconds(1000); serialPort.BaudRate = 9600; serialPort.Parity = SerialParity.None; serialPort.StopBits = SerialStopBitCount.One; serialPort.DataBits = 8; serialPort.Handshake = SerialHandshake.None; // 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; } } catch (Exception ex) { status.Text = ex.Message; } } /// <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(1000); serialPort.ReadTimeout = TimeSpan.FromMilliseconds(1000); serialPort.BaudRate = 9600; serialPort.Parity = SerialParity.None; serialPort.StopBits = SerialStopBitCount.One; serialPort.DataBits = 8; serialPort.Handshake = SerialHandshake.None; // 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; } } /// <summary> /// sendTextButton_Click: Action to take when 'WRITE' button is clicked /// - Create a DataWriter object with the OutputStream of the SerialDevice /// - Create an async task that performs the write operation /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private async void sendTextButton_Click(object sender, RoutedEventArgs e) { try { if (serialPort != null) { // Create the DataWriter object and attach to OutputStream dataWriteObject = new DataWriter(serialPort.OutputStream); //Launch the WriteAsync task to perform the write await WriteAsync(); } else { status.Text = "Select a device and connect"; } } catch (Exception ex) { status.Text = "sendTextButton_Click: " + ex.Message; } finally { // Cleanup once complete if (dataWriteObject != null) { dataWriteObject.DetachStream(); dataWriteObject = null; } } } /// <summary> /// WriteAsync: Task that asynchronously writes data from the input text box 'sendText' to the OutputStream /// </summary> /// <returns></returns> private async Task WriteAsync() { Task<UInt32> storeAsyncTask; if (sendText.Text.Length != 0) { // Load the text from the sendText input text box to the dataWriter object dataWriteObject.WriteString(sendText.Text); // Launch an async task to complete the write operation storeAsyncTask = dataWriteObject.StoreAsync().AsTask(); UInt32 bytesWritten = await storeAsyncTask; if (bytesWritten > 0) { status.Text = sendText.Text + ", "; status.Text += "bytes written successfully!"; } sendText.Text = ""; } else { status.Text = "Enter the text you want to write and then click on 'WRITE'"; } } /// <summary> /// - Create a DataReader object /// - Create an async task to read from the SerialDevice InputStream /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private async void Listen() { try { if (serialPort != null) { dataReaderObject = new DataReader(serialPort.InputStream); // keep reading the serial input while (true) { await ReadAsync(ReadCancellationTokenSource.Token); } } } catch (Exception ex) { if (ex.GetType().Name == "TaskCanceledException") { status.Text = "Reading task was cancelled, closing device and cleaning up"; CloseDevice(); } else { status.Text = ex.Message; } } finally { // Cleanup once complete if (dataReaderObject != null) { dataReaderObject.DetachStream(); dataReaderObject = null; } } } /// <summary> /// ReadAsync: Task that waits on data and reads asynchronously from the serial device InputStream /// </summary> /// <param name="cancellationToken"></param> /// <returns></returns> private async Task ReadAsync(CancellationToken cancellationToken) { Task<UInt32> loadAsyncTask; uint ReadBufferLength = 1024; // If task cancellation was requested, comply cancellationToken.ThrowIfCancellationRequested(); // Set InputStreamOptions to complete the asynchronous read operation when one or more bytes is available dataReaderObject.InputStreamOptions = InputStreamOptions.Partial; // Create a task object to wait for data on the serialPort.InputStream loadAsyncTask = dataReaderObject.LoadAsync(ReadBufferLength).AsTask(cancellationToken); // Launch the task and wait UInt32 bytesRead = await loadAsyncTask; if (bytesRead > 0) { rcvdText.Text = dataReaderObject.ReadString(bytesRead); status.Text = "bytes read successfully!"; } } /// <summary> /// CancelReadTask: /// - Uses the ReadCancellationTokenSource to cancel read operations /// </summary> private void CancelReadTask() { if (ReadCancellationTokenSource != null) { if (!ReadCancellationTokenSource.IsCancellationRequested) { ReadCancellationTokenSource.Cancel(); } } } /// <summary> /// CloseDevice: /// - Disposes SerialDevice object /// - Clears the enumerated device Id list /// </summary> private void CloseDevice() { if (serialPort != null) { serialPort.Dispose(); } serialPort = null; comPortInput.IsEnabled = true; sendTextButton.IsEnabled = false; rcvdText.Text = ""; listOfDevices.Clear(); } /// <summary> /// closeDevice_Click: Action to take when 'Disconnect and Refresh List' is clicked on /// - Cancel all read operations /// - Close and dispose the SerialDevice object /// - Enumerate connected devices /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void closeDevice_Click(object sender, RoutedEventArgs e) { try { status.Text = ""; CancelReadTask(); CloseDevice(); ListAvailablePorts(); } catch (Exception ex) { status.Text = ex.Message; } } } } 

这下一个块如果从我的代码。 ConnectToSerialPort()中的前两行与之前的testing相同，但SerialDevice.FromIdAsync(dis[0].id); 始终为空。 这不行！

 using System; using System.Collections.Generic; using System.Diagnostics; using System.IO; using System.Linq; using Windows.Devices.Enumeration; using Windows.Devices.SerialCommunication; using Windows.Storage.Streams; using Windows.UI.Xaml.Controls; namespace OpenLab.Kitchen.Receiver { public sealed partial class MainPage : Page { private List<byte> Bytes { get; set; } public MainPage() { this.InitializeComponent(); Bytes = new List<byte>(); ConnectToSerialPort(); } private async void ConnectToSerialPort() { var dis = await DeviceInformation.FindAllAsync(SerialDevice.GetDeviceSelectorFromUsbVidPid(0x04D8, 0x000A)); var sp = await SerialDevice.FromIdAsync(dis[0].Id); Debug.WriteLine(sp.UsbVendorId); DeviceInformationCollection serialDevices; while ((serialDevices = await DeviceInformation.FindAllAsync(SerialDevice.GetDeviceSelectorFromUsbVidPid(0x04D8, 0x000A))).Count < 1) { Debug.WriteLine("Unable to locate..."); } SerialDevice serialPort; while ((serialPort = await SerialDevice.FromIdAsync(serialDevices[0].Id)) == null) { Debug.WriteLine("Failed to open serial port..."); } serialPort.WriteTimeout = TimeSpan.FromMilliseconds(1000); serialPort.ReadTimeout = TimeSpan.FromMilliseconds(1000); serialPort.BaudRate = 9600; serialPort.Parity = SerialParity.None; serialPort.StopBits = SerialStopBitCount.One; serialPort.DataBits = 8; serialPort.Handshake = SerialHandshake.None; var dataReader = new DataReader(serialPort.InputStream); var buffer = new byte[1024]; while (true) { var bytesRead = await dataReader.LoadAsync((uint)buffer.Length); dataReader.ReadBytes(buffer); Bytes.AddRange(buffer.Take((int)bytesRead)); byte[] slipPacket; while ((slipPacket = Slip.ExtractSlipPacket(Bytes)) != null) { var waxPacket = WaxPacketConverter.FromBinary(slipPacket, DateTime.Now); if (waxPacket != null) { Debug.WriteLine(waxPacket); } } } } } } 

我已经检查了所有的清单权限来匹配它们，并检查像引用的DLL版本的东西，一切看起来都是一样的。 还检查像pipe理员的VS运行的东西，我没有同时打开这两个应用程序，所以它不应该保持端口打开或任何东西…

有没有人有任何想法？

 <Capabilities> <DeviceCapability Name="serialcommunication"> <Device Id="any"> <Function Type="name:serialPort" /> </Device> </DeviceCapability> </Capabilities>