UWP藍牙LE InvalidCastException

Question

我想將myo腕帶連接到hololens。這是最終目標，但我無論如何，但接近： -/

這個想法是建立一個與UWP的藍牙LE連接。 我想這樣做，因爲在這個Microsoft Document

的設備搜索workes精細explanined，但是當我嘗試連接到一個設備，這條線（點「連接到設備」 ）：GattDeviceServicesResult result = await device.GetGattServicesAsync();

引發錯誤：

System.InvalidCastException: "Unable to cast object of type 'Windows.Devices.Bluetooth.BluetoothLEDevice' to type 'Windows.Devices.Bluetooth.IBluetoothLEDevice3'."

我不知道什麼IBluetoothLEDevice3已經在那裏做:-) 我無法找到關於微軟的文檔了一個解決方案或互聯網： -/

我在Visual Studio 2017上工作，爲Windows 10構建（15063），並且在清單中啓用了藍牙。

這是我的代碼，所以票價。我只添加了一件事，那就是任務。我想確保BluetoothLEDDevice不爲空或任何東西，因爲它不同步。沒有它不工作。

using System; 
using System.Collections.Generic; 
using System.IO; 
using System.Linq; 
using System.Runtime.InteropServices.WindowsRuntime; 
using Windows.Foundation; 
using Windows.Foundation.Collections; 
using Windows.UI.Xaml; 
using Windows.UI.Xaml.Controls; 
using Windows.UI.Xaml.Controls.Primitives; 
using Windows.UI.Xaml.Data; 
using Windows.UI.Xaml.Input; 
using Windows.UI.Xaml.Media; 
using Windows.UI.Xaml.Navigation; 
using System.Diagnostics; 
using Windows.Devices.Enumeration; 
using Windows.Devices.Bluetooth; 
using Windows.Devices.Bluetooth.GenericAttributeProfile; 
using System.Threading.Tasks; 
using Windows.Devices.Bluetooth.Advertisement; 


// Die Elementvorlage "Leere Seite" wird unter https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x407 dokumentiert. 

namespace Bluetooth17 
{ 
    /// <summary> 
    /// Eine leere Seite, die eigenständig verwendet oder zu der innerhalb eines Rahmens navigiert werden kann. 
    /// </summary> 
    public sealed partial class MainPage : Page  
    { 


     public MainPage() 
     { 
      this.InitializeComponent(); 

      blue(); 

     } 



     void blue() 
     { 
      // Query for extra properties you want returned 
      string[] requestedProperties = { "System.Devices.Aep.DeviceAddress", "System.Devices.Aep.IsConnected" }; 

      DeviceWatcher deviceWatcher = 
         DeviceInformation.CreateWatcher(
           BluetoothLEDevice.GetDeviceSelectorFromPairingState(false), 
           requestedProperties, 
           DeviceInformationKind.AssociationEndpoint); 

      // Register event handlers before starting the watcher. 
      // Added, Updated and Removed are required to get all nearby devices 
      deviceWatcher.Added += DeviceWatcher_Added; 
      deviceWatcher.Updated += DeviceWatcher_Updated; 
      deviceWatcher.Removed += DeviceWatcher_Removed; 

      // EnumerationCompleted and Stopped are optional to implement. 
      deviceWatcher.EnumerationCompleted += DeviceWatcher_EnumerationCompleted; 
      deviceWatcher.Stopped += DeviceWatcher_Stopped; 

      // Start the watcher. 
      deviceWatcher.Start(); 
     } 

     private void DeviceWatcher_Stopped(DeviceWatcher sender, object args) 
     { 
      Debug.WriteLine("Stopped"); 
     } 

     private void DeviceWatcher_EnumerationCompleted(DeviceWatcher sender, object args) 
     { 
      Debug.WriteLine("Enum complete"); 
     } 

     private void DeviceWatcher_Removed(DeviceWatcher sender, DeviceInformationUpdate args) 
     { 
      Debug.WriteLine(args.Id + " Removed"); 
     } 

     private void DeviceWatcher_Updated(DeviceWatcher sender, DeviceInformationUpdate args) 
     { 
      Debug.WriteLine(args.Id + " Update"); 
     } 

     private void DeviceWatcher_Added(DeviceWatcher sender, DeviceInformation args) 
     { 
      Debug.WriteLine(args.Id + "  " + args.Name); 

      if (args.Name.Equals("Myo")) 
      { 
       Debug.WriteLine("Try to connect to Myo"); 
       getServices(args); 
      } 
     } 

     async Task<BluetoothLEDevice> ConnectDevice(DeviceInformation deviceInfo) 
     { 
      Debug.WriteLine("Asyc"); 
      // Note: BluetoothLEDevice.FromIdAsync must be called from a UI thread because it may prompt for consent. 
      return await BluetoothLEDevice.FromIdAsync(deviceInfo.Id); 


     } 


     async void getServices(DeviceInformation deviceInfo) 
      { 

      Task<BluetoothLEDevice> task = ConnectDevice(deviceInfo); 

      task.Wait(); 

      BluetoothLEDevice device = task.Result; 

      GattDeviceServicesResult result = await device.GetGattServicesAsync(); 

      if (result.Status == GattCommunicationStatus.Success) 
      { 
       var services = result.Services; 
       // ... 
      } 

     } 
    } 
} 

謝謝

Answer 1

如果您將應用程序創建15063，你知道你要連接到的不僅僅是設備使用：

device = await BluetoothLEDevice.FromBluetoothAddressAsync(blueToothAddress); 

這比你的代碼更加穩定，不需要設備觀察者。 這裏是我的設備工作的例子（不是MIO但HM10）：

using System; 
using System.Diagnostics; 
using Windows.Devices.Bluetooth; 
using Windows.Devices.Bluetooth.GenericAttributeProfile; 
using Windows.UI.Xaml.Controls; 

namespace App1 
{  
    public sealed partial class MainPage : Page 
    { 
     private BluetoothLEDevice device; 
     GattDeviceServicesResult serviceResult = null; 
     public MainPage() 
     { 
     this.InitializeComponent(); 
     StartDevice(); 
     } 

     private async void StartDevice() 
     { 
     //To get your blueToothAddress add: ulong blueToothAddress = device.BluetoothAddress to your old code. 
     ulong blueToothAddress = 88396936323791; //fill in your device address!! 
     device = await BluetoothLEDevice.FromBluetoothAddressAsync(blueToothAddress);   
     if (device != null) 
     { 
      string deviceName = device.DeviceInformation.Name; 
      Debug.WriteLine(deviceName); 
      int servicesCount = 3;//Fill in the amount of services from your device!! 
      int tryCount = 0; 
      bool connected = false; 
      while (!connected)//This is to make sure all services are found. 
      { 
       tryCount++; 
       serviceResult = await device.GetGattServicesAsync(); 

       if (serviceResult.Status == GattCommunicationStatus.Success && serviceResult.Services.Count >= servicesCount) 
       { 
        connected = true; 
        Debug.WriteLine("Connected in " + tryCount + " tries"); 
       } 
       if (tryCount > 5)//make this larger if faild 
       { 
        Debug.WriteLine("Failed to connect to device "); 
        return; 
       } 
      } 
     } 
     } 
    } 
}