Dragging operation randomly stop working

[SangGyu Kim]

"Dragging" operation randomly stop working

I could not find any pattern.

Once it not working it never goes to work until refresh silverlight control.

When it occurred DragInfo event and DragQuery event not fired. 

[Miroslav]

Hi SangGyu Kim,

May you give us more information when this happens?

1. Is this happening in the demos? 
2. Is there an exception (turn on all exceptions if this is a project)
3. What is the value of

 

RadDragAndDropManager.IsDragging;

and

 

 

RadDragAndDropManager.Options.Status;

when this behavior occurs?

4. Is it related to the mouse going out of the browser window or the Silverlight area?

Any extra information will help us pinpoint the problem.

Kind regards,

Miroslav
the Telerik team
Check out Telerik Trainer, the state of the art learning tool for Telerik products.

 

[SangGyu Kim]

Thank you !

This problem  is originated my Datasource of ListBox.

When DataSource list change notifying,  the exception occurred and following drag operation failed.

After I handled the exception the problem is gone.

[ankit]

I am having same problem.

1. Is this happening in the demos?
- > No.
2. Is there an exception (turn on all exceptions if this is a project)
- > No exception ( just stops working )
3. What is the value of RadDragAndDropManager.IsDragging
- > It does not throw any event or error, so, hard to know this value.

What am I doing :
I have 3 observable collection. I am basically assigning values from one to another.
But, at some point of time, it just stops working. No pattern.
I think it needs one more event for error, so, we can trap.
Basically, I have a source all the time, so, It shouldn't be matter, this control should work unless someone find any bug here.

Admin, please guide here as I am struggling with this control.

Thanks.

[Miroslav]

Hi ankit,

I can think of several reasons for this behavior:

1. The routed events do not reach the handlers.
Solution: Check that events are really not fired by adding a handler to the Source object or a Class handler for one of the base classes. Class handlers are added this way:

EventManager.RegisterClassHandler(typeof(FrameworkElement),
 RadDragAndDropManager.DropQueryEvent,
 new EventHandler<DragDropQueryEventArgs>(MyDelegate));

2. The destination is a part of a popup that is not part of the VisualTree, normally these popups will be created and opened in code.
Solution:  Add these detached popups to the ParticipatingVisualRoots collection during DragQuery.

3. Canvases with no background do not receive mouse events.
Solution: Assign a background (even Transparent) to these Canvases.

If these suggestions do not work for you, I will need more information:
Do you use nested drop targets?
Are you using Windows/Popups?
Anything specific in the VisualTree of the App? E.g. - overlays.
Ideally a sample project where this issue appears will help us get to the solution quickly.

Greetings,
Miroslav
the Telerik team

Check out Telerik Trainer, the state of the art learning tool for Telerik products.

[Pablo]

Hi

Same problem

1. Is this happening in the demos?
- > No.
2. Is there an exception (turn on all exceptions if this is a project)
- > No exception ( just stops working )
3. What is the value of RadDragAndDropManager.IsDragging > false
RadDragAndDropManager.Options.Status > none

Drag objects are ListBoxItem. I add this handler but nothing...

 

EventManager.RegisterClassHandler(typeof(ListBoxItem),

 

 

RadDragAndDropManager.DropQueryEvent,

 

 

new EventHandler<DragDropQueryEventArgs>(OnDragQuery));

 

I'm using Blacklight DragDockPanel too in my project.

Regards, Pablo.

[Hristo]

Hello Pablo,

Can you provide a project where we can observe this behavior?
This way it will be a lot easier for us to catch the problem.

Kind regards,
Hristo
the Telerik team

Check out Telerik Trainer, the state of the art learning tool for Telerik products.

[Pablo]

Yes, can you give me an email address to send de code project?

[Vlad]

Hi Pablo,

You can open support ticket where you can attach your project.

Kind regards,
Vlad
the Telerik team

Check out Telerik Trainer, the state of the art learning tool for Telerik products.

[Pablo]

Done

[ankit]

Admin,

Did you come to any conclusion why it's doing so.
In my case, I have same problem.

1. Is this happening in the demos?
- > No.
2. Is there an exception (turn on all exceptions if this is a project)
- > No exception ( just stops working )
3. What is the value of RadDragAndDropManager.IsDragging > false
RadDragAndDropManager.Options.Status > none

I am very frustrated. In my case, most of the time, I drag and drop and that drop makes one or more web service call.
I am locking the interface as well. So, there is not click. Even though I don't need to lock interface for that time.

Can you please release either bug fixed version. Or make RadDragAndDropManager.IsDragging property as a Read and Write, so, if it's stop working means false, we can again make it true. If you want remove this as a Static class. It will be really great help if you can prioritize this control.

Thanks.

Ankit

[Valentin.Stoychev]

Hi ankit,

Yes - we are investigating the problem. We will fix it with the upcoming release. Thank you reporting it.

All the best,
Valentin.Stoychev
the Telerik team

Check out Telerik Trainer, the state of the art learning tool for Telerik products.