bool await "Object reference not set to an instance of an object"
Bonjour,
j'ai cette erreur "Object reference not set to an instance of an object"
Code:
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| var services =
await Windows.Devices.Enumeration.DeviceInformation.FindAllAsync(
RfcommDeviceService.GetDeviceSelector(
RfcommServiceId.ObexObjectPush));
if (services.Count > 0)
{
// Initialize the target Bluetooth BR device
var service = await RfcommDeviceService.FromIdAsync(services[0].Id);
bool res = await IsCompatibleVersion(service);
var dialog = new MessageDialog(res.ToString());
await dialog.ShowAsync();
}
// This App relies on CRC32 checking available in version 2.0 of the service.
private const uint SERVICE_VERSION_ATTRIBUTE_ID = 0x0300;
private const byte SERVICE_VERSION_ATTRIBUTE_TYPE = 0x0A; // UINT32
private const uint MINIMUM_SERVICE_VERSION = 200;
private async System.Threading.Tasks.Task<bool> IsCompatibleVersion(RfcommDeviceService service)
{
var attributes = await service.GetSdpRawAttributesAsync(Windows.Devices.Bluetooth.BluetoothCacheMode.Uncached);
var attribute = attributes[SERVICE_VERSION_ATTRIBUTE_ID];
var reader = DataReader.FromBuffer(attribute);
// The first byte contains the attribute' s type
byte attributeType = reader.ReadByte();
if (attributeType == SERVICE_VERSION_ATTRIBUTE_TYPE)
{
// The remainder is the data
uint version = reader.ReadUInt32();
return version >= MINIMUM_SERVICE_VERSION;
}
return false;
} |
merci
