Drag to specific slot from external source

[Ryszard]

I'm trying to implement dragging from a ListBox onto a ScheduleView, using DragAndDropManager.  I'm as far as the DropInfo handler on the view where the ScheduleView resides running, and am successfully getting the information that I want from the ListBox.  What I can't figure out is how to find out which slot I am trying to drop into.  DragDropEventArgs.Options.CurrentDragPoint would seem a promising way to this information, and the demos show how to so this for the old Scheduler control, but ScheduleView appears to operate differently.  The only other piece of information that I can find suggests that DefaultDragDropBehavior.ValidateExternalDrag "could be used to add the appointments from external source".

Is there a simple example available demonstrating how to drag from an external non-ScheduleView source onto a specific slot within a ScheduldeView in order to create a new appointment based on the dragged-in object?  If not, would it at least be possible to provide some pointers as to how I can achieve this?


Thanks
Ryszard

[Ryszard]

I eventually unearthed RadDragAndDropExtensions.GetNewTime() which looks as though it should do what I'm after.  However, when I call it from DropInfo handler it throws a NullReferenceException:

        private void OnDropInfo(object sender, DragDropEventArgs e)
        {
            if (e.Options.Status == DragStatus.DropComplete)
            {
                DateTime time = RadDragAndDropExtensions.GetNewTime(e);

                MessageBox.Show("Dropping " + e.Options.Payload + " on " + time.ToString());
            }
        }

The DragDropEventArgs (e) is not null, so I guess that GetNewTime() doesn't like something about one of its members.

The DragQuery handler is lifted straight from http://www.telerik.com/help/silverlight/raddraganddrop-items-onto-radscheduler.html:

     private void OnDragQuery(object sender, DragDropQueryEventArgs e)
        {
            if (e.Options.Status == DragStatus.DragQuery)
            {
                var draggedItem = e.Options.Source;
                e.QueryResult = true;
                e.Handled = true;

                // Create Drag and Arrow Cue
                ContentControl dragCue = new ContentControl();
                dragCue.Content = draggedItem.DataContext;
                e.Options.DragCue = dragCue;
                e.Options.ArrowCue = RadDragAndDropManager.GenerateArrowCue();

                // Set the payload (this is the item that is currently dragged)
                e.Options.Payload = draggedItem.DataContext;
            }

            if (e.Options.Status == DragStatus.DropSourceQuery)
            {
                e.QueryResult = true;
                e.Handled = true;
            }
        }


Can anybody see what I'm missing that causes RadDragAndDropExtensions.GetNewTime() to throw the NullReferenceException?


Thanks
Ryszard

[Ryszard]

Also get exactly the same result when I try to drag and drop an appointment within the ScheduleView, which I find suspicious.  The exception details pinpoint the location of the exception:

System.NullReferenceException was unhandled by user code
  Message=Object reference not set to an instance of an object.
  Source=Telerik.Windows.Controls.ScheduleView
  StackTrace:
       at Telerik.Windows.Controls.RadDragAndDropExtensions.GetNewTime(DragDropEventArgs e) in c:\Dev3\branches\2010.Q3.Release\Controls\ScheduleView\ScheduleView\Helpers\DragDropExtensions.cs:line 48

Again, any thoughts on this greatly appreciated, 'cos I'm getting a headache :~)


Thanks
Ryszard

[Rosi]

Hi Ryszard,

Please find the attached project illustrating how to implement drag from a listbox to RadScheduleView.

Do not hesitate to contact us if you need more help.

Greetings,
Rosi
the Telerik team

[Ryszard]

Wow, that looks like a very comprehensive example that covers pretty much everything that I am trying to achieve.  Thank you very much for your help.


Ryszard

[Rod Yager]

I found this sample helpful as well. One thing I haven't been able to figure out is how to get the destination value like resource assigned when dropping. My example is almost exactly like the Schedule View demo of Custom Styles> Group Header Styles. I want to know what resource has been assigned so that I can do some updating in the DB.

SchedulerDragDropPayload payload = e.Options.Payload as SchedulerDragDropPayload;
            if (e.Options.Status == DragStatus.DropComplete && payload != null && e.Options.Source is MetrixListView)
            {
                IList selectedItems = payload.DragDropState.Data as IList;
                foreach (DataRowView drv in selectedItems)
                {
                    //Need to know the destination resource that this payload has been dropped on?
                }
            }

Thanks for any help provided!
Rod

[Rosi]

Hi Rod Yager,

You can access the resources of the destination slot by the following way;

SchedulerDragDropPayload payload = e.Options.Payload as SchedulerDragDropPayload
payload .DragDropState.DestinationSlots.First().Resources;

Kind regards,
Rosi
the Telerik team