前面的部分提供了启动项目的示例和指南，包括：
- 创建简单的模板。
- 实现一个可以通过PosExplorer进行编译和被“服务点”示例应用程序查看的服务对象类。
- 实现线程辅助类。
此示例结合了所有这些步骤来创建一个工作多线程 MSR Service 对象类。 此示例实际上不会从任何硬件读取。 它只是通过系统推送测试数据。 但是，它说明了如何添加特定于服务对象的代码。
为您的服务对象定制此代码
PosAssembly修改AssemblyInfo.cs中的属性，使其包含组织的名称。请确保命名空间的名称适用于组织和服务对象。
修改属性
ServiceObject以包含要创建的服务对象的类型、名称、说明和版本号。添加一个
HardwareId属性，用于将此服务对象与即插即用设备或一系列设备相关联。包括 Service 对象读取器线程简介中显示的 ThreadHelper 类。 为此，可以将代码粘贴到源文件中，或将其编译为项目中的单独源文件。 请确保 ThreadHelper 类位于可访问的命名空间中。
根据服务对象使用的 基 类以及要支持的功能，实现必要的成员。 此示例是一个功能很少的正常运行的 MSR 服务对象。
要求
若要编译此示例，项目必须具有正确的引用和全局属性。 如果尚未为 .NET Service 对象创建工作 POS，请查看 服务对象示例：入门 部分。
此外，还需要将上一部分中的代码“ 服务对象读取器线程简介”包含到项目中。
演示
大多数服务对象需要使用第二个线程来监视硬件并通知应用程序各种传入数据事件。 此示例演示了创建多线程服务对象的一种方法。 它依赖于服务对象读取器线程简介中讨论的 ServiceObjectThreadHelper 类来执行此作。
若要使用帮助程序类，应用程序需要定义实现 ServiceObjectThreadHelper 接口的新类。 此接口包括三种方法：
- ServiceObjectThreadOpen 此方法在线程初始化期间调用，应用于初始化任何特定于硬件的资源。
- ServiceObjectThreadClose 当线程终止并应用于释放任何特定于硬件的资源时，将调用此方法。
- ServiceObjectThreadProcedure 成功启动线程并应循环等待硬件事件后，将调用此方法，在触发正确的 ManualEvent 之前不应退出。
此代码基于主题 “创建服务对象示例 ”中显示的示例，并添加以下功能：
- 创建派生自 ServiceObjectThreadHelper 的类。
- 创建 MsrThreadingObject 类的实例。 此类的构造函数采用单个参数，即对服务对象的引用。
- 从服务对象调用 MsrThreadingObject 对象上的方法，以便根据需要启动和停止线程帮助程序。
Example
using System;
using System.Threading;
using Microsoft.PointOfService;
using Microsoft.PointOfService.BaseServiceObjects;
using System.Text;
namespace Samples.ServiceObjects.Advanced.MSR
{
public class MsrThreadingObject :
ServiceObjectThreadHelper, IDisposable
{
// This is a helper class which will depend on
// being able to call back into the actual Service
// Object to pass along data. However, you cannot
// keep a strong reference to the Service Object,
// since that will prevent proper disposal, which
// may create a state in which all hardware resources
// are not properly released by the SO. Therefore,
// create a weak reference. From this reference,
// you can get a temporary strong reference, which
// you act on and then release.
WeakReference ServiceObjectReference;
// The name of the Service Object.
string ObjectName;
public MsrThreadingObject(AdvancedSampleMsr so)
{
ObjectName = GetType().Name;
ServiceObjectReference = new WeakReference(so);
}
~MsrThreadingObject()
{
Dispose(true);
}
private bool IsDisposed = false;
protected virtual void Dispose(bool disposing)
{
if (!IsDisposed)
{
IsDisposed = true;
base.Dispose(disposing);
}
}
public void Dispose()
{
Dispose(false);
}
#region Methods of ServiceObjectThreadHelper
// This will be called during initialization.
public override void ServiceObjectThreadOpen()
{
Logger.Info(ObjectName, "Msr Thread Open");
}
// This method will be called during shutdown.
public override void ServiceObjectThreadClose()
{
Logger.Info(ObjectName, "Msr Thread Open");
}
public override void ServiceObjectThreadProcedure(
AutoResetEvent ThreadStopEvent)
{
// Convert a C# string into a sample byte array.
UTF8Encoding encoder = new UTF8Encoding();
// Convert sample data to a byte array.
byte[] MsrData = encoder.GetBytes(
"This is MSR test data");
Logger.Info(ObjectName, "Msr Thread Procedure Entered");
while (true)
{
// When this method is called by the
// ServiceObjectThreadHelper, it is obligated to
// exit when the event ThreadStopEvent has been
// set.
// Additionally, this method will also wait for
// hardware events or for a time-out. That should
// be done here.
// This example waits for the event to be set
// or times out after several seconds.
if (ThreadStopEvent.WaitOne(2000, false))
{
break;
}
Logger.Info(ObjectName, "Reader Thread cycling");
// Try to get a strong reference to the Service
// Object using the weak reference saved when
// this helper object was created.
AdvancedSampleMsr msr =
ServiceObjectReference.Target
as AdvancedSampleMsr;
// If this fails, that means the Service
// Object has already been disposed of. Exit the
// thread.
if (msr == null)
{
break;
}
// Using the strong reference, you can now make
// calls back into the Service Object.
msr.OnCardSwipe(MsrData);
msr = null;
}
#endregion Methods of ServiceObjectThreadHelper
}
// Implementation of the Service Object class. This class
// implements all the methods needed for an MSR Service
// Object.
//
// A Service Object which supports a Plug and Play device
// should also have a HardwareId attribute here.
[HardwareId(
@"HID\Vid_05e0&Pid_038a",
@"HID\Vid_05e0&Pid_038a")]
[ServiceObject(
DeviceType.Msr,
"AdvancedSampleMsr",
"Advanced Sample Msr Service Object",
1,
9)]
public class AdvancedSampleMsr : MsrBase
{
// String returned for various health checks.
private string MyHealthText;
private const string PollingStatistic =
"Polling Interval";
// Create a class with interface methods called from the
// threading object.
MsrThreadingObject ReadThread;
public AdvancedSampleMsr()
{
// DevicePath must be set before Open() is called.
// In the case of Plug and Play hardware, the POS
// for .NET Base class will set this value.
DevicePath = "Sample Msr";
Properties.CapIso = true;
Properties.CapTransmitSentinels = true;
Properties.DeviceDescription =
"Advanced Sample Msr";
// Initialize the string to be returned from
// CheckHealthText().
MyHealthText = "";
}
~AdvancedSampleMsr()
{
// Code added from previous sections to terminate
// the read thread started by the thread-helper
// object.
ReadThread.CloseThread();
Dispose(false);
}
protected override void Dispose(bool disposing)
{
try
{
if (disposing)
{
if (ReadThread != null)
{
ReadThread.Dispose();
ReadThread = null;
}
}
}
finally
{
// Must call base class Dispose.
base.Dispose(disposing);
}
}
#region Internal Members
// This is a private method called from the task
// interface when a data event occurs in the reader
// thread.
internal void OnCardSwipe(byte[] CardData)
{
// Simple sample data.
UTF8Encoding utf8 = new UTF8Encoding();
byte[] track1Data = utf8.GetBytes(
"this is test track 1");
byte[] track2Data = utf8.GetBytes(
"this is test track 2");
// Call GoodRead(), UnreadableCard, or FailedRead
// from here.
GoodRead(
track1Data,
track2Data,
null,
null,
Microsoft.PointOfService.BaseServiceObjects.CardType.Iso);
}
#endregion Internal Members
#region PosCommon overrides
// PosCommon.Open.
public override void Open()
{
// Call base class Open.
base.Open();
// Initialize statistic values.
// Set values for common statistics.
SetStatisticValue(StatisticManufacturerName,
"Microsoft Corporation");
SetStatisticValue(
StatisticManufactureDate, "2004-10-23");
SetStatisticValue(
StatisticModelName, "Msr Simulator");
SetStatisticValue(
StatisticMechanicalRevision, "1.0");
SetStatisticValue(
StatisticInterface, "USB");
// Create a new manufacturer statistic.
CreateStatistic(
PollingStatistic,
false,
"milliseconds");
// Set handlers for statistics stored in hardware.
// Create a class with interface methods called
// from the threading object.
ReadThread = new MsrThreadingObject(this);
}
// PosCommon.CheckHealthText.
public override string CheckHealthText
{
get
{
// MsrBasic.VerifyState(mustBeClaimed,
// mustBeEnabled).
VerifyState(false, false);
return MyHealthText;
}
}
// PosCommon.CheckHealth.
public override string CheckHealth(
HealthCheckLevel
level)
{
// Verify that device is open, claimed, and enabled.
VerifyState(true, true);
// Your code here checks the health of the device and
// returns a descriptive string.
// Cache result in the CheckHealthText property.
MyHealthText = "Ok";
return MyHealthText;
}
// PosCommon.DirectIO.
public override DirectIOData DirectIO(
int command,
int data,
object obj)
{
return new DirectIOData(data, obj);
}
public override bool DeviceEnabled
{
get
{
return base.DeviceEnabled;
}
set
{
if (value != base.DeviceEnabled)
{
base.DeviceEnabled = value;
if (value == false)
{
// Stop the reader thread when the
// device is disabled.
ReadThread.CloseThread();
}
else
{
try
{
// Enabling the device, start the
// reader thread.
ReadThread.OpenThread();
}
catch (Exception e)
{
base.DeviceEnabled = false;
if (e is PosControlException)
throw;
throw new PosControlException(
"Unable to Enable Device",
ErrorCode.Failure, e);
}
}
}
}
}
#endregion PosCommon overrides.
#region MsrBasic Overrides
// MsrBasic.MsrFieldData
// Once the track data is retrieved, this method is
// called when the application accesses various data
// properties in the MsrBasic class. For example,
// FirstName and AccountNumber.
protected override MsrFieldData ParseMsrFieldData(
byte[] track1Data,
byte[] track2Data,
byte[] track3Data,
byte[] track4Data,
CardType cardType)
{
// MsrFieldData contains the data elements that
// MsrBasic will return as properties to the
// application, as they are requested.
MsrFieldData data = new MsrFieldData();
// Parse the raw track data and store in fields to
// be used by the app.
data.FirstName = "FirstName";
data.Surname = "LastName";
data.Title = "Mr.";
data.AccountNumber = "123412341234";
return data;
}
// MsrBasic.MsrTrackData.
protected override MsrTrackData ParseMsrTrackData(
byte[] track1Data,
byte[] track2Data,
byte[] track3Data,
byte[] track4Data,
CardType cardType)
{
MsrTrackData data = new MsrTrackData();
// Modify the track data as appropriate for your SO.
// Remove the sentinel characters from the track data,
// for example.
data.Track1Data = (byte[])track1Data.Clone();
data.Track2Data = (byte[])track2Data.Clone();
return data;
}
#endregion MsrBasic overrides
}
}
}
