Drag Drop Issue

4 posts, 0 answers
  1. Matt Eland
    Matt Eland avatar
    24 posts
    Member since:
    Sep 2009

    Posted 11 Jun 2012 Link to this post

    An automated exception report from one of our users contained an ArgumentNull_Generic exception with a stack trace of:

    at Telerik.Windows.Controls.ChildrenOfTypeExtensions.d__3.MoveNext() 
    at System.Linq.Enumerable.d__aa`1.MoveNext() 
    at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source) 
    at Telerik.Windows.Controls.GridView.DragDropHelper.GetElement(Grid cue) 
    at Telerik.Windows.Controls.GridView.DragDropController.OnHeaderCellDragInfo(Object sender, DragDropEventArgs e) 
    at Telerik.Windows.Controls.DragDrop.DragDropEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget) 
    at Telerik.Windows.RadRoutedEventArgs.InvokeHandler(Delegate handler, Object target) 
    at Telerik.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RadRoutedEventArgs routedEventArgs) 
    at Telerik.Windows.EventRoute.InvokeHandlersImpl(Object source, RadRoutedEventArgs args, Boolean raisedAgain) 
    at Telerik.Windows.RadRoutedEventHelper.RaiseEvent(DependencyObject element, RadRoutedEventArgs args) 
    at Telerik.Windows.Controls.DragDrop.RadDragAndDropManager.DragDropProvider_DragInfo(Object sender, DragDropEventArgs e) 
    at Telerik.Windows.Controls.DragDrop.DragDropProviderBase.RaiseDragInfo() 
    at Telerik.Windows.Controls.DragDrop.DragDropProvider.OnDragInitialized(Object sender, DragInitializeEventArgs e) 
    at Telerik.Windows.DragDrop.DragInitializeEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget) 
    at Telerik.Windows.RadRoutedEventArgs.InvokeHandler(Delegate handler, Object target) 
    at Telerik.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RadRoutedEventArgs routedEventArgs) 
    at Telerik.Windows.EventRoute.InvokeHandlersImpl(Object source, RadRoutedEventArgs args, Boolean raisedAgain) 
    at Telerik.Windows.RadRoutedEventHelper.RaiseEvent(DependencyObject element, RadRoutedEventArgs args) 
    at Telerik.Windows.DragDrop.DragInitializer.StartDrag() 
    at Telerik.Windows.DragDrop.DragInitializer.DragSourcePreviewMouseMove(Object sender, MouseEventArgs e) 
    at MS.Internal.CoreInvokeHandler.InvokeEventHandler(UInt32 typeIndex, Delegate handlerDelegate, Object sender, Object args) 
    at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName, UInt32 flags)


    on drag / drop, likely with the grid. Is this a Telerik issue? Is this a problem with our code? This is not something we've encountered before and would like to resolve if possible.
  2. Nick
    Admin
    Nick avatar
    593 posts

    Posted 12 Jun 2012 Link to this post

    Hi Matt,

    Would it be possible to share some more details(implementation, exact actions when the problem can be observed, sample project would be great) about the scenario in which this issue occurs?

    Thank you in advance!  

    All the best,
    Nik
    the Telerik team

    Explore the entire Telerik portfolio by downloading the Ultimate Collection trial package. Get it now >>

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  4. Matt Eland
    Matt Eland avatar
    24 posts
    Member since:
    Sep 2009

    Posted 12 Jun 2012 Link to this post

    Unfortunately, I don't have a lot of details on things as this was just an automated exception report without any repro steps.

    This is a RadTreeGridView with IsDragDropEnabled true, IsDragTooltipEnalbed false, IsDropPreviewLineEnabled true, DropElementAction of None. This is using Q2 2011 SP1.

    I'm not using the hierarchy features of the TreeGridView due to the many bugs and poor performance I encountered with Telerik's RadTreeGridView control that went unresolved far too long and instead do my own hide / expand logic by inserting / removing rows manually. This is unrelated to this issue, but worth mentioning since the control is technically a TreeGridView.

    I support drag / drop to re-order items inside of the grid by looking at DropInfo and DropQuery for the grid. I also support dragging and dropping objects from a sidebar onto individual rows to affect properties on those rows.

    From the stack trace, it looks to me that this issue occurs the first time someone tried to drag a row in the grid, but I don't know.
  5. Nick
    Admin
    Nick avatar
    593 posts

    Posted 15 Jun 2012 Link to this post

    Hi Matt,

    Unfortunately we were not able to reproduce the issue, based on the provided information. Would it be possible to share at least the implementation of the Drag and Drop scenario? Also, have you tried the scenario with a newer version of our product? Does the issue occur even then? 

    Looking forward to your response! 

    All the best,
    Nik
    the Telerik team

    Explore the entire Telerik portfolio by downloading the Ultimate Collection trial package. Get it now >>

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