//Saves the persistance data to an xml file.
void Save(IDictionary <XName, InstanceValue> instanceData)
{
string fileName = IOHelper.GetFileName(this.ownerInstanceID);
XmlDocument doc = new XmlDocument();
doc.LoadXml("<InstanceValues/>");
foreach (KeyValuePair <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);
}
doc.Save(fileName);
}
//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 <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);
}
//The LoadWorkflow command instructs the instance store to lock and load the instance bound to the identifier in the instance handle
else if (command is LoadWorkflowCommand)
{
string fileName = IOHelper.GetFileName(this.ownerInstanceID);
try
{
using (FileStream inputStream = new FileStream(fileName, FileMode.Open))
{
data = LoadInstanceDataFromFile(inputStream);
//load the data into the persistence Context
context.LoadedInstance(InstanceState.Initialized, data, null, null, null);
}
}
catch (Exception exception)
{
throw new PersistenceException(exception.Message);
}
}
return(new CompletedAsyncResult <bool>(true, callback, state));
}