title: BLE Indicate UWP GATT Client
body: <p>I was wondering, if there is a problem with the UWP Bluetooth API and Indicate.
  If I understand the <a href="https://docs.microsoft.com/en-us/windows/uwp/devices-sensors/gatt-client#subscribing-for-notifications" rel="nofollow noreferrer">documentation</a> correctly UWP will handle the Acknowledgment of a received Indicate package. 
  But for some reason, the sample code works for notifys but not for indicates. I am trying this with a Myo Wristband.
  I can receive notifications via notify characteristics but not via the indicates one. Unfortunately I have to use indicate.</p>
  
  <p>I changed the sample code a little bit to this, but its not working:</p>
  
  <pre><code>GattCommunicationStatus status = await selectedCharacteristic.WriteClientCharacteristicConfigurationDescriptorAsync(
      GattClientCharacteristicConfigurationDescriptorValue.Indicate);
  
  if(status == GattCommunicationStatus.Success)
  {
      // Server has been informed of clients interest.
  }
  </code></pre>
  
  <p>and the Handler stays the same:</p>
  
  <pre><code>characteristic.ValueChanged += Characteristic_ValueChanged;
  // ... 
  void Characteristic_ValueChanged(GattCharacteristic sender, 
                                      GattValueChangedEventArgs args)
  {
      // An Indicate or Notify reported that the value has changed.
      var reader = DataReader.FromBuffer(args.CharacteristicValue)
      // Parse the data however required.
  }
  </code></pre>
  
  <p>Any ideas what I am doing wrong? The device is connected and correctly programed, it sends the notifications.</p>
  
  <p>Thanks in Advance for any help</p>
  
  <p>Marcel</p>