LightSensor.ReadingChanged 事件

定义

命名空间:

Windows.Devices.Sensors

每次环境光传感器报告新的传感器读数时发生。

// Register
event_token ReadingChanged(TypedEventHandler<LightSensor, LightSensorReadingChangedEventArgs const&> const& handler) const;

// Revoke with event_token
void ReadingChanged(event_token const* cookie) const;

// Revoke with event_revoker
LightSensor::ReadingChanged_revoker ReadingChanged(auto_revoke_t, TypedEventHandler<LightSensor, LightSensorReadingChangedEventArgs const&> const& handler) const;

public event TypedEventHandler<LightSensor,LightSensorReadingChangedEventArgs> ReadingChanged;

function onReadingChanged(eventArgs) { /* Your code */ }
lightSensor.addEventListener("readingchanged", onReadingChanged);
lightSensor.removeEventListener("readingchanged", onReadingChanged);
- or -
lightSensor.onreadingchanged = onReadingChanged;

Public Custom Event ReadingChanged As TypedEventHandler(Of LightSensor, LightSensorReadingChangedEventArgs) 

事件类型

TypedEventHandler<LightSensor,LightSensorReadingChangedEventArgs>

示例

以下示例演示使用 C# 和 XAML 生成的 UWP 应用如何注册其 ReadingChanged 事件处理程序。

private void ScenarioEnable(object sender, RoutedEventArgs e)
{
    if (_sensor != null)
    {
        // Establish the report interval
        _sensor.ReportInterval = _desiredReportInterval;

        Window.Current.VisibilityChanged += new WindowVisibilityChangedEventHandler(VisibilityChanged);
        _sensor.ReadingChanged += new TypedEventHandler<LightSensor, LightSensorReadingChangedEventArgs>(ReadingChanged);

        ScenarioEnableButton.IsEnabled = false;
        ScenarioDisableButton.IsEnabled = true;
    }
    else
    {
        rootPage.NotifyUser("No light sensor found", NotifyType.StatusMessage);
    }
}

以下示例演示 ReadingChanged 事件处理程序。

async private void ReadingChanged(object sender, LightSensorReadingChangedEventArgs e)
{
    await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
    {
        LightSensorReading reading = e.Reading;
        ScenarioOutput_LUX.Text = String.Format("{0,5:0.00}", reading.IlluminanceInLux);
    });
}

注解

应用程序可以注册此事件处理程序以获取传感器读数。 应用程序必须建立所需的 ReportInterval。 这会通知传感器驱动程序应分配资源以满足应用程序的要求。

应用程序可以通过设置 ReportInterval 属性来设置此事件的频率。