[UWP] [C＃]自动更新读取值 [英] [UWP][C#] auto update read value

问题描述

 private async void CharacteristicsReadButton_Click（）
 {
 // BT_Code：使用Uncached从设备读取实际值。 
 GattReadResult result = await selectedCharacteristic.ReadValueAsync（BluetoothCacheMode.Uncached）; 
 if（result.Status == GattCommunicationStatus.Success）
 {
 string formattedResult = FormatValueByPresentation（result.Value，presentationFormat）; 
 
 rootPage.NotifyUser（$" Read result：{formattedResult}"，NotifyType.StatusMessage）; 
 
} 
 else 
 {
 rootPage.NotifyUser（$" Read failed：{result.Status}"，NotifyType.ErrorMessage）; 
} 
 

我正面临读取值更改的问题。我用我的rfduino设置了mpu5060，所以每当我的rfduino移动时，它会在我的Arduino串口显示器上显示角度。

我的c＃，我可以阅读当我按下"阅读"时的值按钮。但是如果我的值（角度）发生变化，它将不会自动更新以通知用户。我必须手动点击"阅读"按钮再次更改。  如何让
自动更新？

解决方案

您好yann123，

在此处填写文件：订阅通知，您可以订阅  GattCharacteristic.ValueChanged
事件。

您可以使用以下内容代码作为示例：

 GattCommunicationStatus status = await selectedCharacteristic.WriteClientCharacteristicConfigurationDescriptorAsync（
 GattClientCharacteristicConfigurationDescriptorValue.Notify）; 
 if（status == GattCommunicationStatus.Success）
 {
 //服务器已被告知客户的兴趣。 
} 
 
 
 characteristic.ValueChanged + = Characteristic_ValueChanged; 
 
 void Characteristics_ValueChanged（GattCharacteristic sender，
 GattValueChangedEventArgs args）
 {
 //指示或通知报告值已更改。 
 var reader = DataReader.FromBuffer（args.CharacteristicValue）
 //解析所需的数据。 
} 

祝你好运，

罗伊

private async void CharacteristicReadButton_Click()
        {
            // BT_Code: Read the actual value from the device by using Uncached.
            GattReadResult result = await selectedCharacteristic.ReadValueAsync(BluetoothCacheMode.Uncached);
            if (result.Status == GattCommunicationStatus.Success)
            {
                string formattedResult = FormatValueByPresentation(result.Value, presentationFormat);
                
                rootPage.NotifyUser($"Read result: {formattedResult}", NotifyType.StatusMessage);
                
            }
            else
            {
                rootPage.NotifyUser($"Read failed: {result.Status}", NotifyType.ErrorMessage);
            }
        

I'm facing a problem with the read value change. I have setup mpu5060 with my rfduino, so whenever my rfduino moved, it will display the angle on my Arduino serial monitor.

for my c#, I can read the value when I press the "read" button. But if my value(angle) change, it will not auto update to notify user. I have to manually click the "read" button again to change. How do I make it auto update ?

解决方案

Hi yann123,

Form the document here:Subscribing for notifications, you could subscribe the GattCharacteristic.ValueChanged Event after write to Client Characteristic Configuration Descriptor (CCCD).

You could use the following code as example:

GattCommunicationStatus status = await selectedCharacteristic.WriteClientCharacteristicConfigurationDescriptorAsync(
                        GattClientCharacteristicConfigurationDescriptorValue.Notify);
if(status == GattCommunicationStatus.Success)
{
    // Server has been informed of clients interest.
}


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.
}

Best regards,

Roy

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