MagneticStripeReader.ClaimReaderAsync 方法

定义

命名空间:

Windows.Devices.PointOfService

尝试获取对磁条读取器的独占访问权限。

public:
 virtual IAsyncOperation<ClaimedMagneticStripeReader ^> ^ ClaimReaderAsync() = ClaimReaderAsync;

/// [Windows.Foundation.Metadata.RemoteAsync]
IAsyncOperation<ClaimedMagneticStripeReader> ClaimReaderAsync();

[Windows.Foundation.Metadata.RemoteAsync]
public IAsyncOperation<ClaimedMagneticStripeReader> ClaimReaderAsync();

function claimReaderAsync()

Public Function ClaimReaderAsync () As IAsyncOperation(Of ClaimedMagneticStripeReader)

返回

IAsyncOperation<ClaimedMagneticStripeReader>

方法完成后，它将返回 ClaimedMagneticStripeReader ;如果操作无法声明磁条读取器，则返回 null。

属性

RemoteAsyncAttribute

示例

// Claims the magnetic stripe reader for exclusive use
task<void> Scenario1::ClaimReader()
{
    
    return create_task(_reader->ClaimReaderAsync()).then([this] (ClaimedMagneticStripeReader^ claimedReader)
    {
        _claimedReader = claimedReader;
        if (_claimedReader != nullptr)
        {
            // UpdateReaderStatusTextBlock("Magnetic stripe reader claimed successfully.");		
        }
        else
        {
            // UpdateReaderStatusTextBlock("Failed to claim the magnetic stripe reader.");
        }
    });
}

// Claims the magnetic stripe reader for exclusive use.

private async Task<bool> ClaimReader()
{
    if (_claimedReader == null)
    {
        _claimedReader = await _reader.ClaimReaderAsync();

        if (_claimedReader != null)
        {
            // UpdateReaderStatusTextBlock("Magnetic stripe reader claimed successfully.");
        }
        else
        {
            // UpdateReaderStatusTextBlock("Failed to claim a magnetic stripe reader.");
            return false;
        }
    }
    return true;
}

另请参阅

• 磁条读取器示例 (Windows 10)