private bool CanInitiateDragDrop()
{
//Go thru all the selected components and make sure that they can participate in drag drop
ISelectionService selectionService = (ISelectionService)GetService(typeof(ISelectionService));
IDesignerHost designerHost = (IDesignerHost)GetService(typeof(IDesignerHost));
if (selectionService == null || designerHost == null)
return false;
// check if we are cutting root component
ICollection components = selectionService.GetSelectedComponents();
if (components == null || components.Count < 1 || selectionService.GetComponentSelected(designerHost.RootComponent) || !Helpers.AreAllActivities(components))
return false;
return true;
}
private void InitiateDragDrop()
{
WorkflowView parentView = ParentView;
ISelectionService selectionService = (ISelectionService)GetService(typeof(ISelectionService));
IDesignerHost designerHost = (IDesignerHost)GetService(typeof(IDesignerHost));
if (selectionService == null || designerHost == null)
return;
// check if we are cutting root component
ICollection components = selectionService.GetSelectedComponents();
if (components == null || components.Count < 1 || selectionService.GetComponentSelected(designerHost.RootComponent) || !Helpers.AreAllActivities(components))
return;
DragDropEffects effects = DragDropEffects.None;
try
{
// get component serialization service
this.existingDraggedActivities.AddRange(Helpers.GetTopLevelActivities(components));
//IMPORTANT: FOR WITHIN DESIGNER COMPONENT MOVE WE REMOVE THE ACTIVITIES BEFORE WE ADD THEM WHICH IS IN
//ONDRAGDROP FUNCTION. ALTHOUGH THIS VIOLATES THE DODRAGDROP FUNCTION SIMANTICS, WE NEED TO DO THIS
//SO THAT WE CAN USE THE SAME IDS FOR THE ACTIVITIES
DragDropEffects allowedEffects = (DesignerHelpers.AreAssociatedDesignersMovable(this.existingDraggedActivities)) ? DragDropEffects.Move | DragDropEffects.Copy : DragDropEffects.Copy;
IDataObject dataObject = CompositeActivityDesigner.SerializeActivitiesToDataObject(ParentView, this.existingDraggedActivities.ToArray());
effects = parentView.DoDragDrop(dataObject, allowedEffects);
//
}
catch (Exception e)
{
DesignerHelpers.ShowError(ParentView, e.Message);
}
finally
{
//This means drag drop occurred across designer
if (effects == DragDropEffects.Move && this.existingDraggedActivities.Count > 0)
{
string transactionDescription = String.Empty;
if (this.existingDraggedActivities.Count > 1)
transactionDescription = SR.GetString(SR.MoveMultipleActivities, this.existingDraggedActivities.Count);
else
transactionDescription = SR.GetString(SR.MoveSingleActivity, this.existingDraggedActivities[0].GetType());
CompositeActivityDesigner.RemoveActivities(ParentView, this.existingDraggedActivities.AsReadOnly(), transactionDescription);
}
this.existingDraggedActivities.Clear();
}
}
protected override bool OnDragDrop(DragEventArgs eventArgs)
{
//Invalidate the entire rectangle so that we draw active placement glyphs on connectors
WorkflowView parentView = ParentView;
parentView.InvalidateClientRectangle(Rectangle.Empty);
//By default we do not allow any drag drop operation
eventArgs.Effect = DragDropEffects.None;
DestroyDragFeedbackImages();
//Get the coordinates
Point clientPoint = parentView.PointToClient(new Point(eventArgs.X, eventArgs.Y));
Point logicalPoint = parentView.ScreenPointToLogical(new Point(eventArgs.X, eventArgs.Y));
//Now we check if the drag drop was in any valid area, if not then do not proceed further
if (!parentView.IsClientPointInActiveLayout(clientPoint))
{
if (this.dropTargetDesigner != null)
((IWorkflowDesignerMessageSink)this.dropTargetDesigner).OnDragLeave();
this.wasCtrlKeyPressed = false;
this.dropTargetDesigner = null;
this.draggedActivities.Clear();
return false;
}
//Now we have a potential for successful drag drop, so construct drag event arguments with logical coordinates
this.wasCtrlKeyPressed = ((eventArgs.KeyState & 8) == 8);
ActivityDragEventArgs dragdropEventArgs = new ActivityDragEventArgs(eventArgs, this.dragInitiationPoint, logicalPoint, this.draggedActivities);
//Now check which designer is under the cursor, if we have the same designer as the old one
//If not then we set the new one as drop target and pump in messages
HitTestInfo hitTestInfo = MessageHitTestContext;
if (this.dropTargetDesigner != hitTestInfo.AssociatedDesigner)
{
if (this.dropTargetDesigner != null)
{
((IWorkflowDesignerMessageSink)this.dropTargetDesigner).OnDragLeave();
this.dropTargetDesigner = null;
}
if (hitTestInfo.AssociatedDesigner != null)
{
this.dropTargetDesigner = hitTestInfo.AssociatedDesigner;
if (this.dropTargetDesigner != null)
((IWorkflowDesignerMessageSink)this.dropTargetDesigner).OnDragEnter(dragdropEventArgs);
}
}
//We now have appropriate droptarget designer
try
{
if (this.dropTargetDesigner != null)
{
//We do not allow recursive drag and drop
if (!this.wasCtrlKeyPressed && IsRecursiveDropOperation(this.dropTargetDesigner) ||
(this.dropTargetDesigner is CompositeActivityDesigner && !((CompositeActivityDesigner)this.dropTargetDesigner).IsEditable))
{
((IWorkflowDesignerMessageSink)this.dropTargetDesigner).OnDragLeave();
dragdropEventArgs.Effect = DragDropEffects.None;
}
else
{
// IMPORTANT: Don't use draggedActivities variable, because components which are
// there may not be created using the assembly references added to ITypeResultionService
// this.workflowView.time the components will be created using the assembly references got added to the project
List<Activity> droppedActivities = new List<Activity>();
string transactionDescription = SR.GetString(SR.DragDropActivities);
//This means that we are trying to move activities so we use the same activities for drop
if (!this.wasCtrlKeyPressed && this.existingDraggedActivities.Count > 0)
{
droppedActivities.AddRange(this.existingDraggedActivities);
if (droppedActivities.Count > 1)
transactionDescription = SR.GetString(SR.MoveMultipleActivities, droppedActivities.Count);
else if (droppedActivities.Count == 1)
transactionDescription = SR.GetString(SR.MoveSingleActivity, droppedActivities[0].GetType());
}
else
{
droppedActivities.AddRange(CompositeActivityDesigner.DeserializeActivitiesFromDataObject(ParentView, eventArgs.Data, true));
if (droppedActivities.Count > 0)
transactionDescription = SR.GetString(SR.CreateActivityFromToolbox, droppedActivities[0].GetType());
}
//Now that we have what needs to be dropped, we start the actual drag and drop
IDesignerHost designerHost = GetService(typeof(IDesignerHost)) as IDesignerHost;
DesignerTransaction transaction = null;
if (droppedActivities.Count > 0)
transaction = designerHost.CreateTransaction(transactionDescription);
dragdropEventArgs = new ActivityDragEventArgs(eventArgs, this.dragInitiationPoint, logicalPoint, droppedActivities);
try
{
((IWorkflowDesignerMessageSink)this.dropTargetDesigner).OnDragDrop(dragdropEventArgs);
if (dragdropEventArgs.Effect == DragDropEffects.Move)
this.existingDraggedActivities.Clear();
if (transaction != null)
transaction.Commit();
}
catch (Exception e)
{
if (transaction != null)
transaction.Cancel();
throw e;
}
//We deserialize the designers and try to store the designer states
if (droppedActivities.Count > 0)
{
Stream componentStateStream = eventArgs.Data.GetData(DragDropManager.CF_DESIGNERSTATE) as Stream;
if (componentStateStream != null)
Helpers.DeserializeDesignersFromStream(droppedActivities, componentStateStream);
//Set the current selection
ISelectionService selectionService = (ISelectionService)GetService(typeof(ISelectionService));
if (selectionService != null)
selectionService.SetSelectedComponents(droppedActivities, SelectionTypes.Replace);
}
//Active the design surface
if (designerHost != null)
designerHost.Activate();
}
}
}
catch (Exception ex)
{
//We purposely consume application thrown exception which are result of user cancelling the action
//during dragdrop where we popup UI Wizards during drag drop. Ref: InvokeWebService
((IWorkflowDesignerMessageSink)this.dropTargetDesigner).OnDragLeave();
dragdropEventArgs.Effect = DragDropEffects.None;
string dragDropException = ex.Message;
if (ex.InnerException != null && !String.IsNullOrEmpty(ex.InnerException.Message))
dragDropException = ex.InnerException.Message;
string errorMessage = DR.GetString(DR.Error_FailedToDeserializeComponents);
errorMessage += "\r\n" + DR.GetString(DR.Error_Reason, dragDropException);
DesignerHelpers.ShowError(ParentView, errorMessage);
if (ex != CheckoutException.Canceled)
throw new Exception(errorMessage, ex);
}
finally
{
//Make sure that mouse over designer is set to null
this.wasCtrlKeyPressed = false;
this.draggedActivities.Clear();
this.dropTargetDesigner = null;
this.exceptionInDragDrop = false;
eventArgs.Effect = dragdropEventArgs.Effect;
}
return true;
}
