Drag from External Listbox (Null Object Reference Exception) On ScheduleViewDragDropBehavior.Drop)

[Dan]

I'm trying to drag from an external list box to the schedule view control, but i'm getting a "Object reference not set to an instance of an object." Exception in the DragDropBehavior.Drop.

 at Telerik.Windows.Controls.ScheduleViewBase.CreateNew(IAppointment appointment) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Controls\ScheduleView\ScheduleView\Controls\ScheduleView.Editing.cs:line 96
   at Telerik.Windows.Controls.ScheduleViewDragDropBehavior.CopyAppointment(DragDropState state, Slot targetSlot, IAppointment appointment) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Controls\ScheduleView\ScheduleView\DragDropBehavior\ScheduleViewDragDropBehavior.cs:line 447
   at Telerik.Windows.Controls.ScheduleViewDragDropBehavior.Drop(DragDropState state) in c:\TB\102\WPF_Scrum\Release_WPF\Sources\Development\Controls\ScheduleView\ScheduleView\DragDropBehavior\ScheduleViewDragDropBehavior.cs:line 110
   at MAXIS.Scheduling.ScheduleItem.ScheduleViewDragDropBehavior.Drop(DragDropState state) in C:\Projects\_AX\Production\Scheduling\MAXIS.Sch

It's a custom Appointment. I've implemented the copy & the copyfrom methods like is shown in the examples. I can drag & drop from within the control just fine, but dragging a appointment from a listbox throws the exception.  the only difference i see in the state object is that the SourceAppointmentsSource is nothing.

The control version is 2012.1.215.40

[Dan]

Apparently i cannot have a constructor other than the default for my custom appointment items.

[Yana]

Hi Dan,

Please find attached an example which demonstrates how the drag and drop between the ScheduleView and ListBox should be implemented.

Hope this helps.

Greetings,
Yana
the Telerik team

[Siddartha]

System.NullReferenceException

Object reference not set to an instance of an object.

at Microsoft.Windows.Design.Platform.SilverlightMetadataContext.SilverlightXamlExtensionImplementations.<GetXmlNamespaceCompatibilityMappings>d__8.MoveNext() at MS.Internal.Design.Metadata.ReflectionProjectNode.BuildSubsumption() at MS.Internal.Design.Metadata.ReflectionProjectNode.SubsumingNamespace(Identifier identifier) at MS.Internal.Design.Markup.XmlElement.BuildScope(PrefixScope parentScope, IParseContext context) at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.FullParse(Boolean convertToXamlWithErrors) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.get_RootItem() at Microsoft.Windows.Design.DocumentModel.Trees.ModifiableDocumentTree.get_ModifiableRootItem() at Microsoft.Windows.Design.DocumentModel.MarkupDocumentManagerBase.get_LoadState() at MS.Internal.Host.PersistenceSubsystem.Load() at MS.Internal.Host.Designer.Load() at MS.Internal.Designer.VSDesigner.Load() at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedView.Load() at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedDesignerFactory.Load(IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.Load() at MS.Internal.Designer.DesignerPane.LoadDesignerView()

is the exception i m facing
and i cannot see the designer page in silverlight visual studio 2010
i tried installing silverlight5 sdk and toolkit but still can't see the designer page
please help me ..................

[amine]

Hi,

Can you help me please, I have the same error.

 

Please Admin can you update your project

[amine]

problem resolved, ItemsSource must be an ObservableCollection