浅析 自定义PersistenceService类
转载并用C#语言重写，文章很简单，学习用
该例自定义了一个将实例持久化到磁盘文的操作,分两部分
第一部分是实现PersistenceService类,第二部分是操作磁盘的功能类
实现PersistenceService类
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections.Specialized;
using System.Workflow.Runtime;
using System.Workflow.Runtime.Hosting;
using System.Workflow.ComponentModel;
using System.Windows.Forms;
namespace WorkflowLibrary1
{
public class 自定义Persistence服务 : WorkflowPersistenceService
{
/*
当实例进入Idle状态时，引擎是否自动调用unload
为True 时,当实例进入Idle状态时，引擎自动调用实例的unload方法，
具体见 SqlWorkflowPersistenceService类 的
*/
private bool unloadOnIdleValue = false;
/// <summary>
/// 注本服务默认为进入Idle状态的的实例不被引擎自动调用unload方法
/// </summary>
public 自定义Persistence服务()
{
}
/// <summary>
/// 跟据传入的参数，操作当前实例的操作模式值:unloadOnIdleValue
/// </summary>
/// <param name="unloadOnIdle"></param>
public 自定义Persistence服务(bool unloadOnIdle)
{
unloadOnIdleValue = unloadOnIdle;
}
/// <summary>
/// 载入已完成的activity
/// </summary>
/// <param name="scopeId"></param>
/// <param name="outerActivity"></param>
/// <returns></returns>
protected override Activity LoadCompletedContextActivity(Guid scopeId, Activity outerActivity)
{
System.Collections.ArrayList a = new System.Collections.ArrayList();
a.Add("实例:" + scopeId.ToString());
MessageBox.Show("准备:载入已完成的activity:LoadCompletedContextActivity", a.ToString());
object obj = 磁盘文件操作.加载(scopeId, outerActivity);
return obj as Activity;
}
/// <summary>
/// 载入实例
/// </summary>
/// <param name="instanceId"></param>
/// <returns></returns>
protected override Activity LoadWorkflowInstanceState(Guid instanceId)
{
System.Collections.ArrayList a = new System.Collections.ArrayList();
a.Add("实例:" + instanceId.ToString());
MessageBox.Show("准备:载入实例:LoadWorkflowInstanceState", a.ToString());
object obj = 磁盘文件操作.加载(instanceId, null);
return obj as Activity;
}
/// <summary>
/// 保存已完成的状态
/// </summary>
/// <param name="activity"></param>
protected override void SaveCompletedContextActivity(Activity activity)
{
Guid contextGuid = new Guid();
contextGuid = (Guid)activity.GetValue(Activity.ActivityContextGuidProperty);
System.Collections.ArrayList a = new System.Collections.ArrayList();
a.Add("实例:" + contextGuid.ToString());
磁盘文件操作.保存(activity, contextGuid, true);
}
/// <summary>
/// 保存实例
/// </summary>
/// <param name="rootActivity"></param>
/// <param name="unlock"></param>
protected override void SaveWorkflowInstanceState(Activity rootActivity, bool unlock)
{
Guid contextGuid = new Guid();
contextGuid = (Guid)rootActivity.GetValue(Activity.ActivityContextGuidProperty);
System.Collections.ArrayList a = new System.Collections.ArrayList();
a.Add("实例:" + contextGuid.ToString());
a.Add("unlock:" + unlock.ToString());
MessageBox.Show("准备：保存调理：SaveWorkflowInstanceState", a.ToString());
磁盘文件操作.保存(rootActivity, contextGuid, unlock);
}
/// <summary>
/// 返回对进入IDLE状态的实例的解决模式
/// </summary>
/// <param name="activity"></param>
/// <returns></returns>
protected override bool UnloadOnIdle(Activity activity)
{
//为True 时,当实例进入Idle状态时，引擎自动调用实例的unload方法，
Guid contextGuid = new Guid();
contextGuid = (Guid)activity.GetValue(Activity.ActivityContextGuidProperty);
System.Collections.ArrayList a = new System.Collections.ArrayList();
a.Add("模式值:" + unloadOnIdleValue.ToString());
a.Add("实例:" + contextGuid.ToString());
MessageBox.Show("返回对进入IDLE状态的实例的解决模式:UnloadOnIdle", a.ToString());
return unloadOnIdleValue;
}
/// <summary>
/// 对锁定的实例解锁,使实例可被操作
/// </summary>
/// <param name="rootActivity"></param>
protected override void UnlockWorkflowInstanceState(Activity rootActivity)
{
Guid contextGuid;
contextGuid = (Guid)rootActivity.GetValue(Activity.ActivityContextGuidProperty);
System.Collections.ArrayList a = new System.Collections.ArrayList();
a.Add("被解锁的实例:" + contextGuid.ToString());
MessageBox.Show("准备:对锁定的实例解锁:UnlockWorkflowInstanceState", a.ToString());
磁盘文件操作.UnLock(contextGuid);
}
}
}
操作磁盘的功能类
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.IO.Compression;
using System.Collections.Specialized;
using System.Workflow.Runtime;
using System.Workflow.Runtime.Hosting;
using System.Workflow.ComponentModel;
using System.Windows.Forms;
namespace WorkflowLibrary1
{
/// <summary>
/// 该类是将工作流实例保存到磁盘、从磁盘上加载的实体操作类
/// </summary>
class 磁盘文件操作
{
static FileStream 流 = null;
static string 文件名 = null;
/// <summary>
/// 保存activity实例状态到文件
/// </summary>
/// <param name="rootActivity">活动对象</param>
/// <param name="id">Instance的Guid</param>
/// <param name="unlock">是否锁</param>
public static void 保存(Activity rootActivity, Guid id, bool unlock)
{
//以当前工作流的实例ID为文件名
文件名 = id.ToString();
try
{
//如果存在该文件，就删除
if (File.Exists(文件名))
File.Delete(文件名);
//新建流
流 = new FileStream(文件名, FileMode.CreateNew, FileAccess.Write, FileShare.None);
//将工作流实例写入流
rootActivity.Save(流);
}
catch
{
}
finally
{
if (!(流 == null))
流.Close();
}
MessageBox.Show("磁盘文件操作-保存", "保存完成：" + 文件名.ToString());
}
/// <summary>
///
/// </summary>
/// <param name="id">Instance实例ID</param>
/// <param name="outerActivity"></param>
public static object 加载(Guid id, Activity outerActivity)
{
文件名 = id.ToString();
Object obj = null;
try
{
//从磁盘新建流
流 = new FileStream(文件名, FileMode.Open, FileAccess.Read, FileShare.Read);
//从磁盘载入流
流.Seek(0, SeekOrigin.Begin);
obj = Activity.Load(流, outerActivity);
MessageBox.Show("磁盘文件操作-加载", "保存完成:" + 文件名.ToString());
}
catch
{
}
finally
{
流.Close();
}
return obj;
}
/// <summary>
/// 该段代码用于实现对磁盘文件的解锁,如果上面提供了对磁盘文件的锁定操作
/// </summary>
/// <param name="id"></param>
public static void UnLock(Guid id)
{
try
{
文件名 = id.ToString();
流 = new FileStream(文件名, FileMode.Open);
File.SetAttributes(文件名, FileAttributes.Normal);
}
catch
{
}
finally
{
流.Close();
}
MessageBox.Show("磁盘文件操作-解锁", "解锁完成：" + 文件名.ToString());
}
}
}
然后象加载SqlWorkflowPersistenceService类一样使用就可以了
WorkflowRuntime 引擎 = new WorkflowRuntime();
object 自定义PS = new WorkflowLibrary1.自定义Persistence服务(true);
引擎.AddService(自定义PS);
