BleWinrtDll.cpp:429 ScanCharacteristicsAsync catch: 该对象已关闭。

[Amy2048]

It is impossible to obtain the Characteristic and an error message "BleWinrtDll.cpp:429 ScanCharacteristicsAsync catch: This object has been closed." is reported.

[Amy2048]

After the first successful subscription to the feature, closing the application Bluetooth is not disconnected, and running the software again will not be able to obtain characteristicUuid

[Sola-AIGithub]

hello, do you solve this problem?

[Amy2048]

您好，您解决了这个问题吗？

I've fixed the issue, added a method for active disconnect.

[Sola-AIGithub]

May I ask if you are using BleApi.Quit() to do a buffer clear and then reconnect the device, then scan its service & characteristic?
I found that when my device was disconnected, I was able to search for the service but not the characteristic when device reboot.
Since I'm using a one-to-many device connection, I don't want to use BleApi.Quit() to clear the entire buffer!

I'd appreciate any help here.

[Amy2048]

May I ask if you are using BleApi.Quit() to do a buffer clear and then reconnect the device, then scan its service & characteristic? I found that when my device was disconnected, I was able to search for the service but not the characteristic when device reboot. Since I'm using a one-to-many device connection, I don't want to use BleApi.Quit() to clear the entire buffer!

I'd appreciate any help here.

I am using the DLL from the https://github.com/Joelx/BleWinrtDll-Unity-Demo.git library and not the current library's DLL. When I need to exit, calling Quit() disconnects the connection.

[Sola-AIGithub]

I've study BleWinrtDll-Unity-Demo project, it seems like once you call Close(), it will run Quit() to clean all the buffer in BLE connection...
But thanks you help!

[Sola-AIGithub]

Hi @Amy2048 @adabru :
I tried modifying the Quit() function to accept a id from BleApi.DeviceUpdate(), and it successfully allows Windows to disconnect and clear the cache for only the specified device when multiple devices are connected.

Here’s the relevant change I made in BleWinrtDll.cpp:

void Quit(wchar_t* deviceId = nullptr) {
	{
		lock_guard lock(quitLock);
		if (deviceId == nullptr) 
		{
			quitFlag = true;
		}
	}
	StopDeviceScan();
	if (deviceId == nullptr) {
        deviceQueueSignal.notify_one();
        {
            lock_guard lock(deviceQueueLock);
            deviceQueue = {};
        }
        serviceQueueSignal.notify_one();
        {
            lock_guard lock(serviceQueueLock);
            serviceQueue = {};
        }
        characteristicQueueSignal.notify_one();
        {
            lock_guard lock(characteristicQueueLock);
            characteristicQueue = {};
        }
        subscribeQueueSignal.notify_one();
        {
            lock_guard lock(subscribeQueueLock);
            for (auto subscription : subscriptions) {
                if (subscription) {
                    subscription->revoker.revoke();
                    delete subscription;
                }
            }
            subscriptions.clear();
        }
        dataQueueSignal.notify_one();
        {
            lock_guard lock(dataQueueLock);
            dataQueue = {};
        }
        for (auto it = cache.begin(); it != cache.end(); ) {
            for (auto serviceIt = it->second.services.begin(); serviceIt != it->second.services.end(); ) {
                if (serviceIt->second.service != nullptr) {
                    serviceIt->second.service.Close();
                }
                serviceIt = it->second.services.erase(serviceIt);
            }
            if (it->second.device != nullptr) {
                it->second.device.Close();
            }
            it = cache.erase(it);
        }
    } else {
        long deviceHash = hsh(deviceId);
        auto deviceIt = cache.find(deviceHash);
        if (deviceIt != cache.end()) {
            for (auto serviceIt = deviceIt->second.services.begin(); serviceIt != deviceIt->second.services.end(); ) {
                if (serviceIt->second.service != nullptr) {
                    serviceIt->second.service.Close();
                }
                serviceIt = deviceIt->second.services.erase(serviceIt);
            }
            if (deviceIt->second.device != nullptr) {
                deviceIt->second.device.Close();
            }
            cache.erase(deviceIt);
            for (auto it = subscriptions.begin(); it != subscriptions.end(); ) {
                if ((*it) && (*it)->characteristic && (*it)->characteristic.Service().Device().DeviceId() == deviceId) {
                    (*it)->revoker.revoke();
                    delete *it;
                    it = subscriptions.erase(it);
                } else {
                    ++it;
                }
            }
        }
    }
}

After saving the changes, you can build the solution using the outer BleWinrtDll.sln, and the updated BleWinrtDll.dll will be generated under the DebugBle\bin\Debug directory.

• Usage:

BleApi.Quit(); – retains the original behavior: disconnects and clears the cache for all devices

BleApi.Quit(res.id); – disconnects and clears the cache for the specified device only

Hope this helps!

[adabru]

Hi @Sola-AIGithub, thank you very much for posting your solution! The link to your comment is now added in the FAQ of the readme.