ClaimedMagneticStripeReader.ReleaseDeviceRequested 事件

定义

命名空间:

Windows.Devices.PointOfService

当设备收到释放其独占声明的请求时发生。

// Register
event_token ReleaseDeviceRequested(EventHandler<ClaimedMagneticStripeReader> const& handler) const;

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

// Revoke with event_revoker
ClaimedMagneticStripeReader::ReleaseDeviceRequested_revoker ReleaseDeviceRequested(auto_revoke_t, EventHandler<ClaimedMagneticStripeReader> const& handler) const;

public event System.EventHandler<ClaimedMagneticStripeReader> ReleaseDeviceRequested;

function onReleaseDeviceRequested(eventArgs) { /* Your code */ }
claimedMagneticStripeReader.addEventListener("releasedevicerequested", onReleaseDeviceRequested);
claimedMagneticStripeReader.removeEventListener("releasedevicerequested", onReleaseDeviceRequested);
- or -
claimedMagneticStripeReader.onreleasedevicerequested = onReleaseDeviceRequested;

Public Custom Event ReleaseDeviceRequested As EventHandler(Of ClaimedMagneticStripeReader) 

事件类型

EventHandler<ClaimedMagneticStripeReader>

EventHandler<ClaimedMagneticStripeReader>

示例

以下示例演示如何设置事件处理程序。

void Scenario1::ScenarioStartReadButton_Click(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
    create_task(CreateDefaultReaderObject()).then([this](void)
    {
        if (_reader != nullptr)
        {
            // Claim the magnetic stripe reader for exclusive use by your application.
            create_task(ClaimReader()).then([this](void)
            {
                if (_claimedReader)
                {
                    // Add a release device requested event handler. If this event is not handled,  
                    // another app can claim the magnetic stripe reader.
                    _releaseDeviceRequestedToken = _claimedReader->ReleaseDeviceRequested::add(ref new EventHandler<ClaimedMagneticStripeReader^>(this, &Scenario1::OnReleaseDeviceRequested));

                    // Add a data receive event handler.
                    _bankCardDataReceivedToken =  _claimedReader->BankCardDataReceived::add(ref new TypedEventHandler<ClaimedMagneticStripeReader^, MagneticStripeReaderBankCardDataReceivedEventArgs^>(this, &Scenario1::OnBankCardDataReceived));
                    UpdateReaderStatusTextBlock("Attached the BankCardDataReceived event handler..");

                    // Set the app to decode the raw data from the magnetic stripe reader.
                    _claimedReader->IsDecodeDataEnabled = true;

                    // Enable the magnetic stripe reader.
                    create_task(EnableReader()).then([this](void)
                    {
                        UpdateReaderStatusTextBlock("Ready to Swipe..");

                        // Reset the button state
                        ScenarioEndReadButton->IsEnabled = true;
                        ScenarioStartReadButton->IsEnabled = false;

                    });
                }
            });
        }
    });
}

private async void ScenarioStartReadButton_Click(object sender, RoutedEventArgs e)
{
    if (await CreateDefaultMagneticStripeReaderObject())
    {
        if (_reader != null)
        {
            // Claim the reader for exclusive use by your application.
            if (await ClaimReader())
            {
                if (_claimedReader != null)
                {
                    /// Add a release device requested event handler. If this event is not handled,  
                    // another app can claim the magnetic stripe reader.
                    _claimedReader.ReleaseDeviceRequested += OnReleaseDeviceRequested;

                    // Add a data receive event handler.
                    _claimedReader.BankCardDataReceived += OnBankCardDataReceived;
                    UpdateReaderStatusTextBlock("Attached the BankCardDataReceived Event handler..");

                    // Set the app to decode the raw data from the magnetic stripe reader.
                    _claimedReader.IsDecodeDataEnabled = true;

                    // Enable the magnetic stripe reader.
                    if (await EnableReader())
                    {
                        UpdateReaderStatusTextBlock("Ready to Swipe..");

                        // Reset the button state
                        ScenarioEndReadButton.IsEnabled = true;
                        ScenarioStartReadButton.IsEnabled = false;
                    }
                }
            }
        }
    }
}

void Scenario1::OnReleaseDeviceRequested(Platform::Object ^sender, Windows::Devices::PointOfService::ClaimedMagneticStripeReader ^args)
{
    // Always retain the device. If it is not retained, this exclusive claim will be lost.
    args->RetainDevice(); 
}

void OnReleaseDeviceRequested(object sender, ClaimedMagneticStripeReader args)
{
    // Always retain the device. If it is not retained, this exclusive claim will be lost.
    args.RetainDevice(); 
}

另请参阅

• 磁条读取器示例 (Windows 10)