// This method collects view state attached properties and generates a Xaml node stream
// with all view state information appearing within the ViewStateManager node.
// It is called when workflow definition is being serialized to string.
// inputReader - Nodestream with view state information as attached properties on the activity nodes.
// The reader is positioned at the begining of the workflow definition.
// idManager - This component issues running sequence numbers for IdRef.
// Result - Node stream positioned at the begining of the workflow definition with a
// ViewStateManager node containing all view state information.
// Implementation logic:
// 1. Scan the input nodestream Objects for attached properties that need to be converted (VirtualizedContainerService.HintSize and WorkflowViewStateService.ViewState).
// 2. If the Object had a IdRef value then use it otherwise generate a new value.
// 3. Store idRef value and corresponding viewstate related attached property nodes (from step 1)
// in the viewStateInfo dictionary.
// 4. Use the viewStateInfo dictionary to generate ViewStateManager node which is then inserted
// into the end of output nodestream.
public static XamlReader ConvertAttachedPropertiesToViewState(XamlObjectReader inputReader, ViewStateIdManager idManager)
{
// Stack to track StartObject/GetObject and EndObject nodes.
Stack<Frame> stack = new Stack<Frame>();
XamlMember viewStateManager = new XamlMember(ViewStateManager, GetViewStateManager, SetViewStateManager, inputReader.SchemaContext);
XamlMember idRefMember = new XamlMember(IdRef, GetIdRef, SetIdRef, inputReader.SchemaContext);
// Xaml member corresponding to x:Class property of the workflow definition. Used to find x:Class value in the node stream.
XamlMember activityBuilderName = new XamlMember(typeof(ActivityBuilder).GetProperty("Name"), inputReader.SchemaContext);
string activityBuilderTypeName = typeof(ActivityBuilder).Name;
// Dictionary to keep track of IdRefs and corresponding viewstate related
// attached property nodes.
Dictionary<string, XamlNodeList> viewStateInfo = new Dictionary<string, XamlNodeList>();
// Output node list
XamlNodeList workflowDefinition = new XamlNodeList(inputReader.SchemaContext);
using (XamlWriter workflowDefinitionWriter = workflowDefinition.Writer)
{
bool design2010NamespaceFound = false;
bool inIdRefMember = false;
bool inxClassMember = false;
bool skipWritingWorkflowDefinition = false;
bool skipReadingWorkflowDefinition = false;
string xClassName = null;
while (skipReadingWorkflowDefinition || inputReader.Read())
{
skipWritingWorkflowDefinition = false;
skipReadingWorkflowDefinition = false;
switch (inputReader.NodeType)
{
case XamlNodeType.NamespaceDeclaration:
if (inputReader.Namespace.Namespace.Equals(NameSpaces.Design2010, StringComparison.Ordinal))
{
design2010NamespaceFound = true;
}
break;
case XamlNodeType.StartObject:
// Save the Xaml type and clr object on the stack frame. These are used later to generate
// IdRef values and attaching the same to the clr object.
stack.Push(new Frame() { Type = inputReader.Type, InstanceObject = inputReader.Instance });
// If the design2010 namespace was not found add the namespace node
// before the start object is written out.
if (!design2010NamespaceFound)
{
workflowDefinitionWriter.WriteNamespace(new NamespaceDeclaration(NameSpaces.Design2010, NameSpaces.Design2010Prefix));
design2010NamespaceFound = true;
}
break;
case XamlNodeType.GetObject:
// Push an empty frame to balance the Pop operation when the EndObject node
// is encountered.
stack.Push(new Frame() { Type = null });
break;
case XamlNodeType.StartMember:
// Track when we enter IdRef member so that we can save its value.
if (inputReader.Member.Equals(idRefMember))
{
inIdRefMember = true;
}
// Track when we enter x:Class member so that we can save its value.
else if (inputReader.Member.Equals(activityBuilderName))
{
inxClassMember = true;
}
// Start of VirtualizedContainerService.HintSize or WorkflowViewStateService.ViewState property.
else if (IsAttachablePropertyForConvert(inputReader))
{
// The top of stack here corresponds to the activity on which
// the above properties are attached.
if (stack.Peek().AttachedPropertyNodes == null)
{
stack.Peek().AttachedPropertyNodes = new XamlNodeList(inputReader.SchemaContext);
}
// Write the attached property's xaml nodes into the stack.
XamlReader subTreeReader = inputReader.ReadSubtree();
XamlWriter attachedPropertyWriter = stack.Peek().AttachedPropertyNodes.Writer;
while (subTreeReader.Read())
{
attachedPropertyWriter.WriteNode(subTreeReader);
}
// The subtree reader loop put us at the begining of the next node in the input stream.
// So skip reading/writing it out just yet.
skipReadingWorkflowDefinition = true;
skipWritingWorkflowDefinition = true;
}
break;
case XamlNodeType.Value:
// Read and save IdRef/x:Class member values.
// Also update idManager to keep track of prefixes and ids seen.
if (inIdRefMember)
{
string idRef = inputReader.Value as string;
stack.Peek().IdRef = idRef;
idManager.UpdateMap(idRef);
}
else if (inxClassMember)
{
xClassName = inputReader.Value as string;
idManager.UpdateMap(xClassName);
}
break;
case XamlNodeType.EndMember:
// Exit IdRef/x:Class member state.
if (inIdRefMember)
{
inIdRefMember = false;
}
else if (inxClassMember)
{
inxClassMember = false;
}
break;
case XamlNodeType.EndObject:
// Remove an item from the stack because we encountered the end of an object definition.
Frame frameObject = stack.Pop();
// If the object had (viewstate related) attached properties we need to save them
// into the viewStateInfo dictionary.
if (frameObject.AttachedPropertyNodes != null)
{
frameObject.AttachedPropertyNodes.Writer.Close();
// If the object didn't have IdRef, generate a new one.
if (string.IsNullOrWhiteSpace(frameObject.IdRef))
{
// Use the object type name (or x:Class value) to generate a new id.
if (frameObject.Type != null)
{
string prefix = frameObject.Type.Name;
if (frameObject.Type.UnderlyingType != null)
{
prefix = frameObject.Type.UnderlyingType.Name;
}
if (string.CompareOrdinal(prefix, activityBuilderTypeName) == 0 && !string.IsNullOrWhiteSpace(xClassName))
{
frameObject.IdRef = idManager.GetNewId(xClassName);
}
else
{
frameObject.IdRef = idManager.GetNewId(prefix);
}
}
else //Fallback to generating a guid value.
{
frameObject.IdRef = Guid.NewGuid().ToString();
}
// Since we didn't see a IdRef on this object, insert the generated
// viewstate id into the output Xaml node-stream.
workflowDefinitionWriter.WriteStartMember(idRefMember);
workflowDefinitionWriter.WriteValue(frameObject.IdRef);
workflowDefinitionWriter.WriteEndMember();
// Save the generated idRef on the corresponding clr object as well.
if (frameObject.InstanceObject != null)
{
WorkflowViewState.SetIdRef(frameObject.InstanceObject, frameObject.IdRef);
}
}
viewStateInfo[frameObject.IdRef] = frameObject.AttachedPropertyNodes;
}
// We're at the end of input nodestream and have collected data in viewStateInfo
// so we need to create and insert the ViewStateManager nodes into the output nodestream.
if (stack.Count == 0 && viewStateInfo.Count > 0)
{
XamlNodeList viewStateManagerNodeList = CreateViewStateManagerNodeList(viewStateInfo, inputReader.SchemaContext);
XamlReader viewStateManagerNodeReader = viewStateManagerNodeList.GetReader();
// Insert the ViewStateManager nodes into the output node stream.
workflowDefinitionWriter.WriteStartMember(viewStateManager);
while (viewStateManagerNodeReader.Read())
{
workflowDefinitionWriter.WriteNode(viewStateManagerNodeReader);
}
workflowDefinitionWriter.WriteEndMember(); // viewStateManager
}
break;
}
if (!skipWritingWorkflowDefinition)
{
workflowDefinitionWriter.WriteNode(inputReader);
}
}
}
return workflowDefinition.GetReader();
}
// This method collects view state attached properties and generates a Xaml node stream
// with all view state information appearing within the ViewStateManager node.
// It is called when workflow definition is being serialized to string.
// inputReader - Nodestream with view state information as attached properties on the activity nodes.
// The reader is positioned at the begining of the workflow definition.
// idManager - This component issues running sequence numbers for IdRef.
// Result - Node stream positioned at the begining of the workflow definition with a
// ViewStateManager node containing all view state information.
// Implementation logic:
// 1. Scan the input nodestream Objects for attached properties that need to be converted (VirtualizedContainerService.HintSize and WorkflowViewStateService.ViewState).
// 2. If the Object had a IdRef value then use it otherwise generate a new value.
// 3. Store idRef value and corresponding viewstate related attached property nodes (from step 1)
// in the viewStateInfo dictionary.
// 4. Use the viewStateInfo dictionary to generate ViewStateManager node which is then inserted
// into the end of output nodestream.
public static XamlReader ConvertAttachedPropertiesToViewState(XamlObjectReader inputReader, ViewStateIdManager idManager)
{
// Stack to track StartObject/GetObject and EndObject nodes.
Stack <Frame> stack = new Stack <Frame>();
XamlMember viewStateManager = new XamlMember(ViewStateManager, GetViewStateManager, SetViewStateManager, inputReader.SchemaContext);
XamlMember idRefMember = new XamlMember(IdRef, GetIdRef, SetIdRef, inputReader.SchemaContext);
// Xaml member corresponding to x:Class property of the workflow definition. Used to find x:Class value in the node stream.
XamlMember activityBuilderName = new XamlMember(typeof(ActivityBuilder).GetProperty("Name"), inputReader.SchemaContext);
string activityBuilderTypeName = typeof(ActivityBuilder).Name;
// Dictionary to keep track of IdRefs and corresponding viewstate related
// attached property nodes.
Dictionary <string, XamlNodeList> viewStateInfo = new Dictionary <string, XamlNodeList>();
// Output node list
XamlNodeList workflowDefinition = new XamlNodeList(inputReader.SchemaContext);
using (XamlWriter workflowDefinitionWriter = workflowDefinition.Writer)
{
bool design2010NamespaceFound = false;
bool inIdRefMember = false;
bool inxClassMember = false;
bool skipWritingWorkflowDefinition = false;
bool skipReadingWorkflowDefinition = false;
string xClassName = null;
while (skipReadingWorkflowDefinition || inputReader.Read())
{
skipWritingWorkflowDefinition = false;
skipReadingWorkflowDefinition = false;
switch (inputReader.NodeType)
{
case XamlNodeType.NamespaceDeclaration:
if (inputReader.Namespace.Namespace.Equals(NameSpaces.Design2010, StringComparison.Ordinal))
{
design2010NamespaceFound = true;
}
break;
case XamlNodeType.StartObject:
// Save the Xaml type and clr object on the stack frame. These are used later to generate
// IdRef values and attaching the same to the clr object.
stack.Push(new Frame()
{
Type = inputReader.Type, InstanceObject = inputReader.Instance
});
// If the design2010 namespace was not found add the namespace node
// before the start object is written out.
if (!design2010NamespaceFound)
{
workflowDefinitionWriter.WriteNamespace(new NamespaceDeclaration(NameSpaces.Design2010, NameSpaces.Design2010Prefix));
design2010NamespaceFound = true;
}
break;
case XamlNodeType.GetObject:
// Push an empty frame to balance the Pop operation when the EndObject node
// is encountered.
stack.Push(new Frame()
{
Type = null
});
break;
case XamlNodeType.StartMember:
// Track when we enter IdRef member so that we can save its value.
if (inputReader.Member.Equals(idRefMember))
{
inIdRefMember = true;
}
// Track when we enter x:Class member so that we can save its value.
else if (inputReader.Member.Equals(activityBuilderName))
{
inxClassMember = true;
}
// Start of VirtualizedContainerService.HintSize or WorkflowViewStateService.ViewState property.
else if (IsAttachablePropertyForConvert(inputReader))
{
// The top of stack here corresponds to the activity on which
// the above properties are attached.
if (stack.Peek().AttachedPropertyNodes == null)
{
stack.Peek().AttachedPropertyNodes = new XamlNodeList(inputReader.SchemaContext);
}
// Write the attached property's xaml nodes into the stack.
XamlReader subTreeReader = inputReader.ReadSubtree();
XamlWriter attachedPropertyWriter = stack.Peek().AttachedPropertyNodes.Writer;
while (subTreeReader.Read())
{
attachedPropertyWriter.WriteNode(subTreeReader);
}
// The subtree reader loop put us at the begining of the next node in the input stream.
// So skip reading/writing it out just yet.
skipReadingWorkflowDefinition = true;
skipWritingWorkflowDefinition = true;
}
break;
case XamlNodeType.Value:
// Read and save IdRef/x:Class member values.
// Also update idManager to keep track of prefixes and ids seen.
if (inIdRefMember)
{
string idRef = inputReader.Value as string;
stack.Peek().IdRef = idRef;
idManager.UpdateMap(idRef);
}
else if (inxClassMember)
{
xClassName = inputReader.Value as string;
idManager.UpdateMap(xClassName);
}
break;
case XamlNodeType.EndMember:
// Exit IdRef/x:Class member state.
if (inIdRefMember)
{
inIdRefMember = false;
}
else if (inxClassMember)
{
inxClassMember = false;
}
break;
case XamlNodeType.EndObject:
// Remove an item from the stack because we encountered the end of an object definition.
Frame frameObject = stack.Pop();
// If the object had (viewstate related) attached properties we need to save them
// into the viewStateInfo dictionary.
if (frameObject.AttachedPropertyNodes != null)
{
frameObject.AttachedPropertyNodes.Writer.Close();
// If the object didn't have IdRef, generate a new one.
if (string.IsNullOrWhiteSpace(frameObject.IdRef))
{
// Use the object type name (or x:Class value) to generate a new id.
if (frameObject.Type != null)
{
string prefix = frameObject.Type.Name;
if (frameObject.Type.UnderlyingType != null)
{
prefix = frameObject.Type.UnderlyingType.Name;
}
if (string.CompareOrdinal(prefix, activityBuilderTypeName) == 0 && !string.IsNullOrWhiteSpace(xClassName))
{
frameObject.IdRef = idManager.GetNewId(xClassName);
}
else
{
frameObject.IdRef = idManager.GetNewId(prefix);
}
}
else //Fallback to generating a guid value.
{
frameObject.IdRef = Guid.NewGuid().ToString();
}
// Since we didn't see a IdRef on this object, insert the generated
// viewstate id into the output Xaml node-stream.
workflowDefinitionWriter.WriteStartMember(idRefMember);
workflowDefinitionWriter.WriteValue(frameObject.IdRef);
workflowDefinitionWriter.WriteEndMember();
// Save the generated idRef on the corresponding clr object as well.
if (frameObject.InstanceObject != null)
{
WorkflowViewState.SetIdRef(frameObject.InstanceObject, frameObject.IdRef);
}
}
viewStateInfo[frameObject.IdRef] = frameObject.AttachedPropertyNodes;
}
// We're at the end of input nodestream and have collected data in viewStateInfo
// so we need to create and insert the ViewStateManager nodes into the output nodestream.
if (stack.Count == 0 && viewStateInfo.Count > 0)
{
XamlNodeList viewStateManagerNodeList = CreateViewStateManagerNodeList(viewStateInfo, inputReader.SchemaContext);
XamlReader viewStateManagerNodeReader = viewStateManagerNodeList.GetReader();
// Insert the ViewStateManager nodes into the output node stream.
workflowDefinitionWriter.WriteStartMember(viewStateManager);
while (viewStateManagerNodeReader.Read())
{
workflowDefinitionWriter.WriteNode(viewStateManagerNodeReader);
}
workflowDefinitionWriter.WriteEndMember(); // viewStateManager
}
break;
}
if (!skipWritingWorkflowDefinition)
{
workflowDefinitionWriter.WriteNode(inputReader);
}
}
}
return(workflowDefinition.GetReader());
}
