我正在使用后台工作程序进行BLE RSSI级别测试。
我的问题是RunWorkerCompleted事件会在DoWork完成操作之前立即触发。
大部分DoWork事件操作是创建一个广告观察器并等待来自蓝牙低功耗设备的信号。信号水平将从主线程更新,结果处理将在后台工作程序中进行。
这是我调用后台工作程序的时候:
...
worker = new BackgroundWorker();
worker.DoWork += callTestBLE;
worker.RunWorkerCompleted += worker_RunWorkerCompleted;
worker.RunWorkerAsync(RSSI_Label);
}
事件处理程序:
private async void callTestBLE(object sender, DoWorkEventArgs e)
{
BluetoothLEAdvertisementWatcher watcher1 ;
BluetoothLEAdvertisementFilter advertisementFilter1;
int rssiRetries1 = RSSIRETRIES;
RssiValue = "";
advertisementFilter1 = new BluetoothLEAdvertisementFilter();
try
{
advertisementFilter1.Advertisement.LocalName = myUswm.getAdvetrismentName();
checkRSSI = true;
}
catch (Exception) { checkRSSI = false; return; }
watcher1 = new BluetoothLEAdvertisementWatcher(advertisementFilter);
watcher1.ScanningMode = BluetoothLEScanningMode.Active;
watcher1.Received += OnAdvertisementReceived;
// Wait 5 seconds to make sure the device is really out of range
watcher1.SignalStrengthFilter.OutOfRangeTimeout = TimeSpan.FromMilliseconds(5000);
watcher1.SignalStrengthFilter.SamplingInterval = TimeSpan.FromMilliseconds(2000);
try
{
watcher1.Start();
await testBLEAsync();
if (myUswm.getConnectionStatus() == DISCONNECTED)
{
checkNextUUTClick(new object(), new RoutedEventArgs()); return;
}
for (int i = 0; i < 5; i++)
{
// if (RssiSamplesNum <= 0 || --rssiRetries < 0)
if (RssiSamplesNum <= 0 || --rssiRetries1 < 0)
{
//serviceList.Clear();
watcher1.Stop();
rssiRetries1 = RSSIRETRIES;
RssiSamplesNum1 = numOfAdvertismentSamples;
break;
}
else
{
((Label)e.Argument).Content = RssiValue;
/*RSSI_Label.Dispatcher.Invoke(new Action(() =>
{ RSSI_Label.Content = RssiValue; }));*/
}
Thread.Sleep(2000);
}
}
catch (Exception err) { }
}
private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
finalizeBleTest();
}
感谢任何帮助!
async void
应该用于“Fire & Forget”代码,因为调用代码无法跟踪完成情况。所以我建议您的DoWork
方法不应该是async
的。可以使用BackgroundWorker
或者使用async
/await
,但一般情况下不要尝试将它们结合在一起。 - undefined