"GattDeviceServicesResult" can not be found - visual-studio

Question

I am trying to create client side app using C# for BluetoothLE in VisualStudio 2015 on Windows-10 laptop.
I have problem using Windows.Devices.Bluetooth.GenericAttributeProfile, the issue is my code has compile error saying GattDeviceServicesResult can not be found.
-> I have added package UwpDesktop 10.0.14393.3 by Valdimir Postel... (before installing this even "using Wndows.Devices.Bluetooth" was not working)
-> Then I added SDK, windows Kit that was recommended by VisualStudio when I tried to open one of the example (So I accept the recommendation to build that project and VS installed packages of around 9GB)
-> now I can use some of the Bluetooth api's I can scan and connect to a BLE device, but I can not use classes to deal with services and characteristics because GattDeviceServicesResult and GattCharacteristicsResult types are not found. Although these are mentioned on MSDN website
-> searching in forums I came to know I need to add one more reference System.Runtime.WindowsRuntime.dll, I browsed to proper folder through add reference utility of VS, I am trying to add this and it does nothing, after I select the dll and click 'Add' just nothing happens. (Add reference is not adding this dll).
Just for example if I select some other dll and try to add, that works fine!
Could somebody please help me with this,
using Windows.Devices.Bluetooth;
using Windows.Devices.Bluetooth.GenericAttributeProfile;
using Windows.Devices.Bluetooth.Advertisement;
Int16 uuid_count = 0;
BluetoothLEAdvertisement[] ble_adv = new BluetoothLEAdvertisement[5];
BluetoothLEAdvertisementReceivedEventArgs[] ble_received_adv = new BluetoothLEAdvertisementReceivedEventArgs[5];
BluetoothLEDevice bluetooth_LE_Device;
GattDeviceServicesResult result_service;// This line does not compile
//Error: CS0246 the type name 'GattDeviceServicesResult ' could not be found
// I am adding reference to "System.Runtime.WindowsRuntime" as mentioned in some solutions
// the reference does not seems to be added at first when I click add button, but I can see the reference dll being mentioned in solution explorer (assuming it's been added)
// using this to scan available devices
private void scann_ble()
{
var watcher = new BluetoothLEAdvertisementWatcher();
watcher.Received += Watcher_Received;
watcher.AdvertisementFilter.Advertisement.ServiceUuids.Clear();
watcher.Start();
while (true)
{
Thread.Sleep(10000);
break;
}
watcher.Stop();
}
// receiver event to collect addresses of available devices
private void Watcher_Received(BluetoothLEAdvertisementWatcher sender, BluetoothLEAdvertisementReceivedEventArgs args)
{
bool update_adv = true;
Int16 i = 0;
if(uuid_count < 5)
{
if (uuid_count > 0)
{
while (i < uuid_count)
{
if (ble_received_adv[i].BluetoothAddress == args.BluetoothAddress)
update_adv = false;
i++;
}
}
if(update_adv != false)
ble_received_adv[uuid_count++] = args;
}
}
// now connecting and checking available services
// as per "https://learn.microsoft.com/en-us/windows/uwp/devices-sensors/gatt-client"
private async void BLE_connect_button_Click(object sender, EventArgs e)
{
int i = 0;
i = BLE_device_grid_view.CurrentCell.RowIndex; // getting index from item selected in gridView
bluetooth_LE_Device = await BluetoothLEDevice.FromBluetoothAddressAsync(ble_received_adv[i].BluetoothAddress);
// Connection works fine, I can see it on my peripheral device
//get services - This is not working
result_service = bluetooth_LE_Device.GetGattServicesAsync();
if (result_service.Status == await GattCommunicationStatus.Success)
{
var services = result_service.Services;
// ...
}
}
I am using UwpDesktop package.

Answer 1

I had the same problem. My problem was solved after I changed the reference to windows.winmd from C:\Program Files (x86)\Windows Kits\10\UnionMetadata\windows.winmd to C:\Program Files (x86)\Windows Kits\10\UnionMetadata\10.0.17763.0\windows.winmd.
I'm using BLE 4.0 in a WinForm application and I'm working with Visual Studio 2017.
It is very likely that the directory 10.0.17763.0 doesn't exist on every computer, but you may look what versions of windows.winmd exists on your computer.