The BLE Device Disconnection not working on UWP C#

Question

The BLE Device Disconnection not working on UWP C#

Manickavasagam C 0

Hello folks,
I'm developing a UWP Application using a C# for establishing the connection between BLE devices like Connect, Read, Write, and Disconnect for that we using a "Windows.Devices.Bluetooth".

I'd successfully completed a few operations like connect, Read, and Write. But when I'm trying to disconnect that connected BLE Device, It does not disconnect the device properly, It takes more than 1.5 - 2 mins. Yeah, I had unsubscribed the notification so the data that we are receiving from the BLE Device was stopped. So, that is not a problem.

The only issue should be that the device not disconnecting from the system.
For Example:
connected_device.Dispose();

If anyone has a solution for this issue, please help me.
Thanks in advance!

Junjie Zhu - MSFT 9,596 Reputation points

2023-09-04T02:39:24.01+00:00

Hi @Manickavasagam C ,

Welcome to Microsoft Q&A!

Have you checked the GattSessionStatus? According to this document Bluetooth GATT Client , you should make sure that there is no other app on the system has a reference to the device.

Thank you.

Manickavasagam C 0

Hello @Junjie Zhu - MSFT

Thanks for your time and response

Let me share, How I'm done a connection and disconnecting the device

Connect To Device

  public static async Task<bool> ConnectToDevice(string lastSixId)
        {
            try
            {
                BluetoothLEDevice previous_connected_device = LocalStorage.GetData_BLE_Device(Constants.DEFAULT_CONNECTED_BLE_DEVICE_SESSION_KEY_NAME);

                //await Logger.AddLog(LogLevel.Info, $"Previous Connected device Address: {previous_connected_device.BluetoothAddress.ToString()}");
                if (previous_connected_device != null && previous_connected_device.ConnectionStatus == BluetoothConnectionStatus.Connected)
                {
                    if (characteristic != null)
                    {
                        characteristic.ValueChanged -= Characteristic_ValueChanged;
                        previous_connected_device.ConnectionStatusChanged -= ConnectedDevice_ConnectionStatusChanged;

                        bool UnSubcribed = await UnsubscribeFromNotificationsAsync(previous_connected_device, serviceUuid, characteristicUuid);

                        if (UnSubcribed)
                        {
                            await Logger.AddLog(LogLevel.Info, $"Attempting to disconnect from Device: {previous_connected_device.Name}  -----  Current Connection Status: {previous_connected_device.ConnectionStatus}");
                            

                            DisconnectDeviceAsync(previous_connected_device);
                            // Assuming the Dispose method should handle the disconnection
                            //previous_connected_device.Dispose();
                            //bool isDisconnected = await DisconnectBLEDevice(previous_connected_device);
                            //await Logger.AddLog(LogLevel.Info, "BLE Device Disconnected: " + isDisconnected);

                            // Increase the delay to ensure the device has enough time to update its status
                            await Task.Delay(5000);

                            await Logger.AddLog(LogLevel.Info, $"Status after attempting disconnection, Device Name: {previous_connected_device.Name}  -----  Connection Status: {previous_connected_device.ConnectionStatus}");

                            Constants.DEVICE_SETTING_PREVIOUS_CONNECTED_DEVICE_NAME = previous_connected_device.Name;
                            StatusManagement(Constants.STATE_PREVIOUS_DEVICE_DISCONNECTED);
                            // If the device is still connected after Disconnect, log an error or handle accordingly
                            //if (previous_connected_device.ConnectionStatus == BluetoothConnectionStatus.Connected)
                            //{
                            //    Constants.DEVICE_SETTING_PREVIOUS_CONNECTED_DEVICE_NAME = previous_connected_device.Name;

                            //    previous_connected_device.Dispose();
                            //    StatusManagement(Constants.STATE_PREVIOUS_DEVICE_DISCONNECTED);
                            //}
                            previous_connected_device = null;
                            LocalStorage.Store_BluetoothLEDevice(Constants.DEFAULT_CONNECTED_BLE_DEVICE_SESSION_KEY_NAME, null);
                            LocalStorage.Store_String(Constants.SAVED_DEVICE_SESSION_KEY_NAME, "");

                            characteristic = null;
                        }
                        else
                        {
                            await Logger.AddLog(LogLevel.Error, "Unsubscribed to notifications was failed");
                        }
                    }
                    else
                    {
                        await Logger.AddLog(LogLevel.Error, "characteristic is null for the previous connected device");
                    }
                }

                var bluetoothAddress = ulong.Parse(lastSixId.Replace(":", ""), System.Globalization.NumberStyles.HexNumber);

                await Logger.AddLog(LogLevel.Info, $"Bluetooth Address: {bluetoothAddress.ToString()}");

                BluetoothLEDevice connectedDevice = await BluetoothLEDevice.FromBluetoothAddressAsync(bluetoothAddress);
                if (connectedDevice != null)
                {
                    bool IsSubscribed = await SubscribeToNotificationsAsync(connectedDevice, serviceUuid, characteristicUuid);

                    if (IsSubscribed)
                    {
                        bool IsStarted = await StartDataReceiveTask(connectedDevice);
                        if (IsStarted)
                        {
                            LocalStorage.Store_String(Constants.SAVED_DEVICE_SESSION_KEY_NAME, lastSixId);
                            LocalStorage.Store_BluetoothLEDevice(Constants.DEFAULT_CONNECTED_BLE_DEVICE_SESSION_KEY_NAME, connectedDevice);

                            Constants.CURRENT_CONNECTED_DEVICE = connectedDevice;
                            StatusManagement(Constants.STATE_CONNECTED);

                            return true;
                        }
                        else
                        {
                            await Logger.AddLog(LogLevel.Info, $"NOT STARTED!");
                        }
                    }
                    else
                    {
                        await Logger.AddLog(LogLevel.Info, $"NOT SUBCRIBED");
                    }
                }
                else
                {
                    await Logger.AddLog(LogLevel.Info, "BluetoothLEDevice is null");
                }
            }
            catch (Exception ex)
            {
                await Logger.AddLog(LogLevel.Info, $"Error on Connect_To_Devices: {ex.ToString()}");
            }
            return false;
        }

Yes, From the above method which I'm sharing, I have checked if Is there any previously connected device, If yes, I'm trying to disconnect and connect to a new BLE Device by using a below line

 BluetoothLEDevice connectedDevice = await BluetoothLEDevice.FromBluetoothAddressAsync(bluetoothAddress);

Here is the method for disconnection

 private static async Task<bool> DisconnectDeviceAsync(BluetoothLEDevice device)
        {
            bool success = true;

            try
            {
                var servicesResult = await device.GetGattServicesAsync();
                if (servicesResult.Status == GattCommunicationStatus.Success)
                {
                    foreach (var service in servicesResult.Services)
                    {
                        service.Dispose();
                    }
                }

                //device = null;
            }
            catch (Exception ex)
            {
                await Logger.AddLog(LogLevel.Error, $"Expection while disconnect the device: {ex}");
                success = false;
            }

These are code which I have used before.

Junjie Zhu - MSFT 9,596 Reputation points

2023-09-04T08:06:37.9266667+00:00

Can this official sample help you? It uses GattClientCharacteristicConfigurationDescriptorValue.None to clear the CCCD.

Manickavasagam C 0

I will try that GattClientCharacteristicConfigurationDescriptorValue.None

        private async Task<bool> DisconnectDevice(BluetoothLEDevice device)
        {
            if (characteristic != null)
            {
                var result = await characteristic.WriteClientCharacteristicConfigurationDescriptorAsync(GattClientCharacteristicConfigurationDescriptorValue.None);
                if (result != GattCommunicationStatus.Success)
                {
                    return false;
                }
                else
                {
                    characteristic.ValueChanged -= Characteristic_ValueChanged;
                }
            }
            device?.Dispose();
            int n = 0;
            while (device.ConnectionStatus != BluetoothConnectionStatus.Disconnected)
            {
                await Task.Delay(1000); // Wait for the device to disconnect
                Debug.WriteLine($"Checking Disconnection Status!, Delay Seconds: {n}");
                n++;
            }
            device = null;
            return true;
        }

It more than a 4min, Still the device not disconnecting from the system.

Junjie Zhu - MSFT 9,596 Reputation points

2023-09-04T09:58:49.5966667+00:00

Can this behavior be reproduced on other devices?
Manickavasagam C 0 Reputation points

2023-09-04T10:16:49.75+00:00

Yes, I'm Developing a UWP Application. When I'm trying to new device, I want to disconnect the previous connected device. At times, When I use the device.Dispose(); The device is not disconnected from the system( When I check with my windows Bluetooth, it shows Connected(1));
Junjie Zhu - MSFT 9,596 Reputation points

2023-09-05T08:50:18.5933333+00:00

How about setting bluetoothLeDevice = null directly after Dispose() like the official sample?
Roy Li - MSFT 29,781 Reputation points Microsoft Vendor

2023-09-15T01:39:21.7266667+00:00

Any updates about this issue? Have checked Junjie Zhu's suggestion?

Junjie Zhu - MSFT 9,596 Reputation points

2023-09-04T02:39:24.01+00:00

Hi @Manickavasagam C ,

Welcome to Microsoft Q&A!

Have you checked the GattSessionStatus? According to this document Bluetooth GATT Client , you should make sure that there is no other app on the system has a reference to the device.

Thank you.
Junjie Zhu - MSFT 9,596 Reputation points

2023-09-04T08:06:37.9266667+00:00

Can this official sample help you? It uses GattClientCharacteristicConfigurationDescriptorValue.None to clear the CCCD.
Manickavasagam C 0 Reputation points

2023-09-04T09:30:30.41+00:00

I will try that GattClientCharacteristicConfigurationDescriptorValue.None

private async Task<bool> DisconnectDevice(BluetoothLEDevice device) { if (characteristic != null) { var result = await characteristic.WriteClientCharacteristicConfigurationDescriptorAsync(GattClientCharacteristicConfigurationDescriptorValue.None); if (result != GattCommunicationStatus.Success) { return false; } else { characteristic.ValueChanged -= Characteristic_ValueChanged; } } device?.Dispose(); int n = 0; while (device.ConnectionStatus != BluetoothConnectionStatus.Disconnected) { await Task.Delay(1000); // Wait for the device to disconnect Debug.WriteLine($"Checking Disconnection Status!, Delay Seconds: {n}"); n++; } device = null; return true; }

It more than a 4min, Still the device not disconnecting from the system.
Junjie Zhu - MSFT 9,596 Reputation points

2023-09-04T09:58:49.5966667+00:00

Can this behavior be reproduced on other devices?
Manickavasagam C 0 Reputation points

2023-09-04T10:16:49.75+00:00

Yes, I'm Developing a UWP Application. When I'm trying to new device, I want to disconnect the previous connected device. At times, When I use the device.Dispose(); The device is not disconnected from the system( When I check with my windows Bluetooth, it shows Connected(1));
Junjie Zhu - MSFT 9,596 Reputation points

2023-09-05T08:50:18.5933333+00:00

How about setting bluetoothLeDevice = null directly after Dispose() like the official sample?
Roy Li - MSFT 29,781 Reputation points Microsoft Vendor

2023-09-15T01:39:21.7266667+00:00

Any updates about this issue? Have checked Junjie Zhu's suggestion?

The BLE Device Disconnection not working on UWP C#

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