[Solved] Drag from RadTreeView to RadGridView - TreeViewDragDropOptions always null

[Mike]

I need to determine if the issue is my version of the implementation of drag/drop or if I am missing something in code.  The version we are using is 2013.3.1204.1050 (I realize it is old however very stable for us).

The issue I am having is on the grid's drag/drop behavior, the TreeViewDragDropOptions returns back as null when dragged from the TreeView to the grid.  I have no idea why when the argument's data property contains the object being dragged over to the grid.  Any help would be appreciative.

XAML:

Resources -

<DataTemplate x:Name="ShiftRouteRun">
    <StackPanel>
        <TextBlock Text="{Binding RouteRunCode}" />
    </StackPanel>
</DataTemplate>

<telerik:HierarchicalDataTemplate x:Name="ShiftPlanTemplate"
                                  ItemsSource="{Binding RouteRuns}"
                                  ItemTemplate="{StaticResource ShiftRouteRun}">
    <StackPanel>
        <TextBlock Text="{Binding ShiftTimeDescription}">
            <telerik:RadContextMenu.ContextMenu>
                <telerik:RadContextMenu Opened="RadContextMenu_Opened">
                    <telerik:RadMenuItem Header="Edit" />
                </telerik:RadContextMenu>
            </telerik:RadContextMenu.ContextMenu>
        </TextBlock>
    </StackPanel>
</telerik:HierarchicalDataTemplate>

 

<telerik:RadTreeView x:Name="tvShifts"
                                     ItemTemplate="{StaticResource ShiftPlanTemplate}"
                                     IsEditable="True"
                                     ItemEditTemplate="{StaticResource ShiftEditTemplate}"
                                     IsDragDropEnabled="True"
                                     Grid.Column="0"
                                     Grid.Row="1" />

<telerik:RadGridView x:Name="dgAvailableRuns"
                                     RowStyle="{StaticResource GridDropStyle}"
                                     AllowDrop="True"
                                     AutoGenerateColumns="False"
                                     IsReadOnly="True"
                                     SelectionMode="Single"
                                     ShowGroupPanel="False"
                                     RowIndicatorVisibility="Collapsed"
                                     IsSynchronizedWithCurrentItem="false"
                                     FrozenColumnCount="1"
                                     Height="200"
                                     local:RouteShiftPlanGridViewDropBehavior.IsEnabled="True"
                                     Grid.Column="1"
                                     Grid.Row="1">
                    <telerik:RadGridView.Resources>
                        <DataTemplate x:Key="DragItemTemplate">
                            <StackPanel>
                                <StackPanel Orientation="Horizontal">
                                    <TextBlock Text="Dragging:" />
                                    <TextBlock Text="{Binding RouteRunCode}"
                                               FontWeight="Bold" />
                                </StackPanel>
                            </StackPanel>
                        </DataTemplate>
                    </telerik:RadGridView.Resources>
                    <telerik:RadGridView.Columns>
                        <telerik:GridViewDataColumn ShowDistinctFilters="False"
                                                    DataMemberBinding="{Binding RouteRunCode}" />
                        <telerik:GridViewDataColumn ShowDistinctFilters="False"
                                                    DataMemberBinding="{Binding SchoolDescription}" />
                        <telerik:GridViewDataColumn ShowDistinctFilters="False"
                                                    DataMemberBinding="{Binding DistrictDescription}" />
                        <telerik:GridViewDataColumn ShowDistinctFilters="False"
                                                    DataMemberBinding="{Binding CalendarDescription}" />
                    </telerik:RadGridView.Columns>
                </telerik:RadGridView>

 

Behavior:

Imports Telerik.Windows.Controls
Imports Telerik.Windows.DragDrop
Imports System.Collections

''' <summary>
''' For drag/drop handlers on a RadGridView control
''' </summary>
Public Class RouteShiftPlanGridViewDropBehavior

    Private _associatedObject As RadGridView
    Private Shared instances As Dictionary(Of RadGridView, RouteShiftPlanGridViewDropBehavior)

#Region " Constructors "
    Shared Sub New()
        instances = New Dictionary(Of RadGridView, RouteShiftPlanGridViewDropBehavior)()
    End Sub
#End Region

#Region " Public Properties "
    ''' <remarks>For binding to a RadGridView control</remarks>
    Public Shared ReadOnly IsEnabledProperty As DependencyProperty =
        DependencyProperty.RegisterAttached("IsEnabled", GetType(Boolean), GetType(RouteShiftPlanGridViewDropBehavior), New PropertyMetadata(New PropertyChangedCallback(AddressOf OnIsEnabledPropertyChanged)))

    ''' <summary>
    ''' AssociatedObject Property
    ''' </summary>
    Public Property AssociatedObject As RadGridView
        Get
            Return _associatedObject
        End Get
        Set(value As RadGridView)
            _associatedObject = value
        End Set
    End Property
#End Region

#Region " Methods "
    Public Shared Function GetIsEnabled(obj As DependencyObject) As Boolean
        Return CBool(obj.GetValue(IsEnabledProperty))
    End Function

    Public Shared Sub OnIsEnabledPropertyChanged(dependencyObject As DependencyObject, e As DependencyPropertyChangedEventArgs)
        SetIsEnabled(dependencyObject, CBool(e.NewValue))
    End Sub

    Public Shared Sub SetIsEnabled(obj As DependencyObject, value As Boolean)
        Dim behavior As RouteShiftPlanGridViewDropBehavior = GetAttachedBehavior(TryCast(obj, RadGridView))
        behavior.AssociatedObject = TryCast(obj, RadGridView)

        If value Then
            behavior.Initialize()
        Else
            behavior.CleanUp()
        End If

        obj.SetValue(IsEnabledProperty, value)
    End Sub

    Private Shared Function GetAttachedBehavior(gridView As RadGridView) As RouteShiftPlanGridViewDropBehavior
        If Not instances.ContainsKey(gridView) Then
            instances(gridView) = New RouteShiftPlanGridViewDropBehavior()
            instances(gridView).AssociatedObject = gridView
        End If

        Return instances(gridView)
    End Function

    Protected Overridable Sub Initialize()
        UnsubscribeFromDragDropEvents()
        SubscribeToDragDropEvents()
    End Sub

    Protected Overridable Sub CleanUp()
        Me.UnsubscribeFromDragDropEvents()
    End Sub

    Private Sub SubscribeToDragDropEvents()
        DragDropManager.AddDragInitializeHandler(Me.AssociatedObject, AddressOf OnDragInitialize)
        DragDropManager.AddGiveFeedbackHandler(Me.AssociatedObject, AddressOf OnGiveFeedback)
        DragDropManager.AddDropHandler(Me.AssociatedObject, AddressOf OnDrop)
        DragDropManager.AddDragDropCompletedHandler(Me.AssociatedObject, AddressOf OnDragDropCompleted)
        DragDropManager.AddDragOverHandler(Me.AssociatedObject, AddressOf OnDragOver)
    End Sub

    Private Sub UnsubscribeFromDragDropEvents()
        DragDropManager.RemoveDragInitializeHandler(Me.AssociatedObject, AddressOf OnDragInitialize)
        DragDropManager.RemoveGiveFeedbackHandler(Me.AssociatedObject, AddressOf OnGiveFeedback)
        DragDropManager.RemoveDropHandler(Me.AssociatedObject, AddressOf OnDrop)
        DragDropManager.RemoveDragDropCompletedHandler(Me.AssociatedObject, AddressOf OnDragDropCompleted)
        DragDropManager.RemoveDragOverHandler(Me.AssociatedObject, AddressOf OnDragOver)
    End Sub

    Private Sub OnDragInitialize(sender As Object, args As DragInitializeEventArgs)
        Dim data As RouteRun = TryCast(DirectCast(args.OriginalSource, FrameworkElement).DataContext, RouteRun)

        If data Is Nothing Then
            args.Cancel = True
            Return
        End If

        Dim details As New DropIndicatorHelper()
        details.CurrentDraggedItem = data

        Dim payload As Telerik.Windows.DragDrop.Behaviors.IDragPayload = Telerik.Windows.DragDrop.DragDropPayloadManager.GeneratePayload(Nothing)
        payload.SetData(GetType(RouteRun), data)
        payload.SetData("DropDetails", details)

        Dim visual As New ContentControl()
        With visual
            .Content = data
            .ContentTemplate = TryCast(Me.AssociatedObject.Resources("DragItemTemplate"), DataTemplate)
        End With

        args.Data = payload
        args.DragVisual = visual
        args.DragVisualOffset = args.RelativeStartPoint
        args.AllowedEffects = DragDropEffects.All
    End Sub

    Private Sub OnGiveFeedback(ByVal sender As Object, ByVal args As Telerik.Windows.DragDrop.GiveFeedbackEventArgs)
        args.SetCursor(Cursors.Hand)
        args.Handled = True
    End Sub

    Private Sub OnDrop(sender As Object, e As Telerik.Windows.DragDrop.DragEventArgs)
        Dim options As TreeView.TreeViewDragDropOptions = TryCast(DragDropPayloadManager.GetDataFromObject(e.Data, TreeView.TreeViewDragDropOptions.Key), TreeView.TreeViewDragDropOptions)
        If options Is Nothing Then
            Return
        End If

        Dim draggedItem = options.DraggedItems.FirstOrDefault()
        If draggedItem Is Nothing Then
            Return
        End If

        If e.Effects <> DragDropEffects.None Then
            Dim collection As IList = TryCast(TryCast(sender, RadGridView).ItemsSource, IList)
            collection.Add(draggedItem)
        End If

        e.Handled = True
    End Sub

    Private Sub OnDragDropCompleted(sender As Object, e As DragDropCompletedEventArgs)
        Dim draggedItem = DragDropPayloadManager.GetDataFromObject(e.Data, GetType(RouteRun))

        If e.Effects <> DragDropEffects.None Then
            Dim collection As IList = TryCast(TryCast(sender, RadGridView).ItemsSource, IList)
            collection.Remove(draggedItem)
        End If
    End Sub

    Private Sub OnDragOver(sender As Object, e As Telerik.Windows.DragDrop.DragEventArgs)
        Dim options As TreeView.TreeViewDragDropOptions = TryCast(DragDropPayloadManager.GetDataFromObject(e.Data, TreeView.TreeViewDragDropOptions.Key), TreeView.TreeViewDragDropOptions)
        If options Is Nothing Then
            e.Effects = DragDropEffects.None
            e.Handled = True
            Return
        End If

        Dim draggedItem = options.DraggedItems.FirstOrDefault()
        Dim itemsType As Type = TryCast(Me.AssociatedObject.ItemsSource, IList).AsQueryable().ElementType

        If draggedItem.[GetType]() IsNot itemsType Then
            e.Effects = DragDropEffects.None
        Else
            TryCast(options.DragVisual, TreeView.TreeViewDragVisual).IsDropPossible = True
            options.DropAction = TreeView.DropAction.Move
            options.UpdateDragVisual()
        End If

        e.Handled = True
    End Sub
#End Region

End Class

[Polya]

Hello Mike,

We have a great example about drag and drop between RadTreeView and RadGridView in our QSF examples: http://demos.telerik.com/silverlight/#DragAndDrop/TreeToGrid.
In this example the extracted object from the DragDropPayloladManager is of type DropIndicationDetails that holds information about the dragged item as well. You can try and use it instead of TreeViewDragDropOptions.
Hope this helps.

Regards,
Polya
Telerik by Progress