前幾節提供了範例與啟動專案的指南，包括：
- 建立一個簡單的範本。
- 實作一個服務物件類別，該類別可由 Point Of Service 範例應用程式 PosExplorer編譯並可見。
- 實作一個線程輔助類別。
本範例結合了上述所有步驟，建立一個可運作的多執行緒 MSR 服務物件類別。 這個樣本實際上並沒有從任何硬體讀取。 它只是將測試資料推送到系統中。 不過，它說明了如何加入專屬於你的服務物件的程式碼。
若要自訂此程式碼以符合您的服務物件
修改
PosAssemblyAssemblyInfo.cs 中的屬性，使其包含你組織的名稱。請確保命名空間的名稱適合您的組織與服務物件。
修改
ServiceObject屬性，使其包含你所建立服務物件的類型、名稱、描述和版本號。新增
HardwareId屬性，將此服務物件與即插即用裝置或一系列裝置關聯起來。請包含在《介紹服務物件閱讀執行緒》中所呈現的 ThreadHelper 類別。 你可以把程式碼貼到原始碼檔案，或是編譯成專案中的獨立原始碼檔來達成。 請確保 ThreadHelper 類別位於可存取的命名空間中。
根據服務物件所使用的 基底 類別以及你想支援的功能，實作所需的成員。 此範例是一個功能極少的 MSR 服務物件。
需求
要編譯這個範例，你的專案必須擁有正確的參考資料和全域屬性。 如果你還沒建立一個可運作的 .NET 服務物件 POS，請參考服務 物件範例：開始 說明章節。
此外，你還需要將前一節「 介紹服務物件閱讀執行緒」的程式碼納入你的專案中。
演示
大多數服務物件需要使用第二執行緒來監控硬體並通知應用程式各種資料事件。 此範例展示了建立多執行緒服務物件的一種方法。 它依賴於《引入服務物件讀取執行緒》中討論的 ServiceObjectThreadHelper 類別來達成此目的。
要使用 helper 類別，應用程式需要定義一個新的類別來實作 ServiceObjectThreadHelper 介面。 此介面包含三種方法：
- ServiceObjectThreadOpen 此方法在執行緒初始化時被呼叫，並應用於初始化任何硬體專屬資源。
- ServiceObjectThreadClose 此方法在執行緒終止時呼叫，並用於釋放任何硬體專屬資源。
- 服務物件線程程序 當執行緒成功啟動後，此方法會被呼叫，並應循環等待硬體事件，且在觸發正確的 ManualEvent 前不應退出。
本程式碼建立在「 建立服務物件範例 」主題中展示的範例基礎上，並新增以下功能：
- 建立一個由 ServiceObjectThreadHelper 衍生的類別。
- 建立 一個 MsrThreadingObject 類別的實例。 此類別的建構子接受一個參數，即服務物件的參考。
- 從服務物件呼叫 MsrThreadingObject 物件上的方法，以適當啟動或停止執行緒輔助器。
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
}
}
}
