MAUI 蓝牙自定义配对：如何提示用户输入蓝牙设备上显示的配对 PIN 码以完成配对？

Question

基本上就是主题所说的。我有一个蓝牙设备，每次我尝试使用 Windows 10 机器与其配对时，它都会在屏幕上显示 PIN。我需要在 .Net8 MAUI 应用程序中显示某种弹出对话框，以便用户输入所述 PIN，以便将其提交到 BLE 窗口堆栈。我当前的代码如下所示：

using Windows.Devices.Bluetooth;
using Windows.Devices.Bluetooth.GenericAttributeProfile;
using Windows.Devices.Enumeration;

public static class BluetoothPairing
{

        public async Task<bool> PairAsync(BluetoothLEDevice bluetoothLeDevice, DevicePairingProtectionLevel devicePairingProtectionLevel = DevicePairingProtectionLevel.Default)
        {
            if (bluetoothLeDevice.DeviceInformation.Pairing.IsPaired) //order
                return true;
            
            var canPair = bluetoothLeDevice.DeviceInformation.Pairing.CanPair; //order
            if (!canPair)
                return false;
            
            try
            {
                bluetoothLeDevice.DeviceInformation.Pairing.Custom.PairingRequested += PairingRequestedHandler_;
                
                const DevicePairingKinds allowedDevicePairingKinds = DevicePairingKinds.ConfirmOnly
                                                                     | DevicePairingKinds.DisplayPin
                                                                     | DevicePairingKinds.ProvidePin
                                                                     | DevicePairingKinds.ConfirmPinMatch
                                                                     | DevicePairingKinds.ProvidePasswordCredential; //supported only by Windows10.0.18362.0 and later
                
                 var pairingStatus = DevicePairingResultStatus.Failed;
                 var pairingResult = await bluetoothLeDevice.DeviceInformation.Pairing.Custom.PairAsync(
                        pairingKindsSupported: allowedDevicePairingKinds,
                        minProtectionLevel: devicePairingProtectionLevel
                    );
                    pairingStatus = pairingResult?.Status ?? DevicePairingResultStatus.Failed;
        
                 return pairingStatus is DevicePairingResultStatus.Paired or DevicePairingResultStatus.AlreadyPaired;
            }
            finally
            {
                bluetoothLeDevice.DeviceInformation.Pairing.Custom.PairingRequested -= PairingRequestedHandler_;
            }
      }
}

我的主要问题是我找不到在 PairingRequestedHandler_() 内显示 MAUI 输入对话框的正确方法，因为无论我做什么，UI 都会挂起。我找不到解决这个看似微不足道的问题的方法，我已经束手无策了：

static async void PairingRequestedHandler_(DeviceInformationCustomPairing sender, DevicePairingRequestedEventArgs ea)
{
    //var deferral = ea.GetDeferral();
    // var tcs = new TaskCompletionSource();
    
    var appCurrent = Application.Current;
    if (appCurrent == null)
        return;
    
    var mainPage = Application.Current?.MainPage;
    if (mainPage == null)
        return;
    
    await appCurrent.Dispatcher.DispatchAsync(async () =>
    {
        //var deferral = ea.GetDeferral();
        try
        {
            var typedPin = await mainPage.DisplayPromptAsync(
                title: "Enter Pairing PIN",
                message: $"Type the PIN (ea.Pin='{ea.Pin}') displayed on the device to proceed:",
                accept: "OK",
                cancel: "Cancel"
            );
            
            if (string.IsNullOrEmpty(typedPin))
                return;
            
            ea.Accept(typedPin);
        }
        catch (Exception ex) //if a dialog is already open we will definitely get an exception
        {
            //tcs.TrySetException(ex);
        }
        finally
        {
            //deferral.Complete();
            
            // if (!tcs.Task.IsFaulted)
            // {
            //     tcs.TrySetCompleted(); // deferral.Complete();    
            // }
        }
    });
    
    // tcs.Task.GetAwaiter().GetResult(); //couldnt find a different way to wait for the async code to finish inside the handler
    
    // await tcs.Task;
}

Answer 1

我的主要问题是我找不到在 PairingRequestedHandler_() 内显示 MAUI 输入对话框的正确方法，因为无论我做什么，UI 都会挂起。

您可以将代码放入

MainThread.BeginInvokeOnMainThread()

:

    MainThread.BeginInvokeOnMainThread(() => 
    {
        //display a MAUI input-dialog
    });

有关 MainThread 的更多信息，您可以查看官方文档：在 .NET MAUI UI 线程上创建线程。