WF4提供了强大的持久化的功能,ms提供了SqlWorkflowInstanceStore 来进行SqlServer的持久化,我研究了一下,DB里面有10个数据表,24个存储过程。功能非常强大,但是也逻辑也比较复杂。这里我介绍自定义的持久化。持久化的存储器也SqlServer。
1、设计数据表,表结构非常简单,如下图所示:
2、自定义的SqlServerWorkflowInstanceStore继承了InstanceStore:
{
public Guid ownerInstanceID;
public SqlServerWorkflowInstanceStore() : this(Guid.NewGuid())
{
}
public SqlServerWorkflowInstanceStore(Guid id)
{
ownerInstanceID = id;
}
//Synchronous version of the Begin/EndTryCommand functions
protected override bool TryCommand(InstancePersistenceContext context, InstancePersistenceCommand command, TimeSpan timeout)
{
return EndTryCommand(BeginTryCommand(context, command, timeout, null, null));
}
//The persistence engine will send a variety of commands to the configured InstanceStore,
//such as CreateWorkflowOwnerCommand, SaveWorkflowCommand, and LoadWorkflowCommand.
//This method is where we will handle those commands
protected override IAsyncResult BeginTryCommand(InstancePersistenceContext context, InstancePersistenceCommand command, TimeSpan timeout, AsyncCallback callback, object state)
{
IDictionary<System.Xml.Linq.XName, InstanceValue> data = null;
//The CreateWorkflowOwner command instructs the instance store to create a new instance owner bound to the instanace handle
if (command is CreateWorkflowOwnerCommand)
{
context.BindInstanceOwner(ownerInstanceID, Guid.NewGuid());
}
//The SaveWorkflow command instructs the instance store to modify the instance bound to the instance handle or an instance key
else if (command is SaveWorkflowCommand)
{
SaveWorkflowCommand saveCommand = (SaveWorkflowCommand)command;
data = saveCommand.InstanceData;
Save(data);
}
else if (command is LoadWorkflowCommand)
{
try
{
InstancesTable obj = InstancesTableBiz.GetInstancesTable(this.ownerInstanceID);
System.Text.UTF8Encoding utf8 = new System.Text.UTF8Encoding();
byte[] bs = utf8.GetBytes(obj.InstanceXML);
System.IO.MemoryStream memoryStream = new System.IO.MemoryStream(bs);
data = LoadInstanceDataFromFile(memoryStream);
context.LoadedInstance(InstanceState.Initialized, data, null, null, null);
}
catch (Exception exception)
{
throw new PersistenceException(exception.Message);
}
}
return new CompletedAsyncResult<bool>(true, callback, state);
}
protected override bool EndTryCommand(IAsyncResult result)
{
return CompletedAsyncResult<bool>.End(result);
}
IDictionary<System.Xml.Linq.XName, InstanceValue> LoadInstanceDataFromFile(Stream inputStream)
{
IDictionary<System.Xml.Linq.XName, InstanceValue> data = new Dictionary<System.Xml.Linq.XName, InstanceValue>();
NetDataContractSerializer s
= new NetDataContractSerializer();XmlReader rdr
= XmlReader.Create(inputStream);XmlDocument doc = new XmlDocument();
doc.Load(rdr);
XmlNodeList instances
= doc.GetElementsByTagName("InstanceValue");foreach (XmlElement instanceElement in instances)
{
XmlElement keyElement = (XmlElement)instanceElement.SelectSingleNode("descendant::key");
System.Xml.Linq.XName key = (System.Xml.Linq.XName)DeserializeObject(s, keyElement);
XmlElement valueElement
= (XmlElement)instanceElement.SelectSingleNode("descendant::value");object value = DeserializeObject(s, valueElement);
InstanceValue instVal = new InstanceValue(value);
data.Add(key, instVal);
}
return data;
}
object DeserializeObject(NetDataContractSerializer serializer, XmlElement element)
{
object deserializedObject = null;
MemoryStream stm
= new MemoryStream();XmlDictionaryWriter wtr = XmlDictionaryWriter.CreateTextWriter(stm);
element.WriteContentTo(wtr);
wtr.Flush();
stm.Position = 0;
deserializedObject
= serializer.Deserialize(stm);return deserializedObject;
}
void Save(IDictionary<System.Xml.Linq.XName, InstanceValue> instanceData)
{
XmlDocument doc = new XmlDocument();
doc.LoadXml("<InstanceValues/>");
foreach (KeyValuePair<System.Xml.Linq.XName,InstanceValue> valPair in instanceData)
{
XmlElement newInstance = doc.CreateElement("InstanceValue");
XmlElement newKey
= SerializeObject("key", valPair.Key, doc);newInstance.AppendChild(newKey);
XmlElement newValue
= SerializeObject("value", valPair.Value.Value, doc);newInstance.AppendChild(newValue);
doc.DocumentElement.AppendChild(newInstance);
}
if (!string.IsNullOrEmpty(InstancesTableBiz.GetInstancesTable(this.ownerInstanceID).InstanceXML))
{
InstancesTable obj = InstancesTableBiz.GetInstancesTable(this.ownerInstanceID);
obj.InstanceXML = doc.InnerXml;
InstancesTableBiz.UpdateInstancesTable(obj);
}
else
{
InstancesTable obj = new InstancesTable();
obj.id = this.ownerInstanceID;
obj.InstanceXML = doc.InnerXml;
InstancesTableBiz.AddInstancesTable(obj);
}
}
XmlElement SerializeObject(
string elementName, object o, XmlDocument doc){
NetDataContractSerializer s = new NetDataContractSerializer();
XmlElement newElement = doc.CreateElement(elementName);
MemoryStream stm = new MemoryStream();
s.Serialize(stm, o);
stm.Position = 0;
StreamReader rdr = new StreamReader(stm);
newElement.InnerXml = rdr.ReadToEnd();
return newElement;
}
}
3、设计书签类:
{
public Read()
: base()
{
}
public string BookmarkName { get; set; }
// Must return true for a NativeActivity that creates a bookmark
protected override bool CanInduceIdle
{
get { return true; }
}
protected override void Execute(NativeActivityContext context)
{
context.CreateBookmark(this.BookmarkName, new BookmarkCallback(this.Continue));
}
void Continue(NativeActivityContext context, Bookmark bookmark, object obj)
{
this.Result.Set(context, (TResult)obj);
}
}
4、设计三个书签的流程:
5、自定义持久化的使用
WorkflowApplication application
= new WorkflowApplication(new Activity1());application.InstanceStore
= instanceStore;application.PersistableIdle
= (e) =>{
return PersistableIdleAction.Unload;
};
application.Completed = (workflowApplicationCompletedEventArgs) =>
{
Console.WriteLine("\nWorkflowApplication has Completed in the {0} state.", workflowApplicationCompletedEventArgs.CompletionState);
};
application.Unloaded
= (workflowApplicationEventArgs) =>{
Console.WriteLine("WorkflowApplication has Unloaded\n");
instanceUnloaded.Set();
};
instanceStore.ownerInstanceID
= application.Id;// continue executing this instance
application.Run();
//string a= application.GetBookmarks()[0].BookmarkName;
instanceUnloaded.WaitOne();
return application.Id; ;
6、Demo说明:
在Start.aspx,启动一个流程
在Default.aspx,进行A,B,C三个站的审核。
备注:运行环境是VS2010 BETA2。
代码:/Files/zhuqil/WorkflowConsoleApplication3.rar