Cannot get DragDrop events to fire

[Charles]

I am attempting to get the RadDragAndDrop manager working between two listboxes. I have used the sample code provided in the Examples solution as a guide. Basically the only difference between my code and the code in the example is the data being handled. I am getting a list of custom objects using WCF calls instead of hardcoding the list.

I have wired up all events as in the example, have put breakpoints on all of them, but they never fire. Here is a sample of the code:

    public class DraggableListBox : ListBox
    {
        Brush listBoxDefaultBrush;
        Brush listBoxDragPossible = new SolidColorBrush(Colors.Orange);

        public event EventHandler<DragDropQueryEventArgs> DragQuery
        {
            add
            {
                this.AddHandler(RadDragAndDropManager.DropQueryEvent, value);
            }
            remove
            {
                this.RemoveHandler(RadDragAndDropManager.DragQueryEvent, value);
            }
        }

        public event EventHandler<DragDropQueryEventArgs> DropQuery
        {
            add
            {
                this.AddHandler(RadDragAndDropManager.DropQueryEvent, value);
            }
            remove
            {
                this.RemoveHandler(RadDragAndDropManager.DropQueryEvent, value);
            }
        }

        public event EventHandler<DragDropEventArgs> DragInfo
        {
            add
            {
                this.AddHandler(RadDragAndDropManager.DragInfoEvent, value);
            }
            remove
            {
                this.RemoveHandler(RadDragAndDropManager.DragInfoEvent, value);
            }
        }

        public event EventHandler<DragDropEventArgs> DropInfo
        {
            add
            {
                this.AddHandler(RadDragAndDropManager.DropInfoEvent, value);
            }
            remove
            {
                this.RemoveHandler(RadDragAndDropManager.DropInfoEvent, value);
            }
        }

        public DraggableListBox()
        {
            RadDragAndDropManager.SetAllowDrop(this, true);

            this.DragQuery += new EventHandler<DragDropQueryEventArgs>(OnDragQuery);
            this.DragInfo += new EventHandler<DragDropEventArgs>(OnDragInfo);
            this.DropQuery += new EventHandler<DragDropQueryEventArgs>(OnDropQuery);
            this.DropInfo += new EventHandler<DragDropEventArgs>(OnDropInfo);

        }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
            listBoxDefaultBrush = BorderBrush;
        }

        void OnDropInfo(object sender, DragDropEventArgs e)
        {
            DraggableListBox box = sender as DraggableListBox;
            IList<RuleDTO> itemsSource = box.ItemsSource as IList<RuleDTO>;
            RuleDTO payload = e.Options.Payload as RuleDTO;

            if (e.Options.Status == DragStatus.DropPossible)
            {
                box.BorderBrush = listBoxDragPossible;
            }
            else
            {
                box.BorderBrush = listBoxDefaultBrush;
            }

            if (e.Options.Status == DragStatus.DropComplete)
            {
                if (!itemsSource.Contains(payload))
                {
                    itemsSource.Add(payload);
                }
            }
        }

        void OnDropQuery(object sender, DragDropQueryEventArgs e)
        {
            DraggableListBox box = sender as DraggableListBox;
            IList<RuleDTO> itemsSource = box.ItemsSource as IList<RuleDTO>;
            RuleDTO payload = e.Options.Payload as RuleDTO;

            e.QueryResult = payload != null && !itemsSource.Contains(payload);
        }

        void OnDragInfo(object sender, DragDropEventArgs e)
        {
            DraggableListBox box = sender as DraggableListBox;
            IList<RuleDTO> itemsSource = box.ItemsSource as IList<RuleDTO>;
            RuleDTO payload = e.Options.Payload as RuleDTO;

            if (e.Options.Status == DragStatus.DragComplete)
            {
                if (payload != null && itemsSource.Contains(payload))
                {
                    itemsSource.Remove(payload);
                }
            }
        }

        protected virtual void OnDragQuery(object sender, DragDropQueryEventArgs e)
        {
            DraggableListBox box = sender as DraggableListBox;

            e.QueryResult = true;
            if (e.Options.Status == DragStatus.DragQuery)
            {
                e.Options.SourceCueHost = null;
                e.Options.Payload = box.SelectedItem;
                ContentControl cue = new ContentControl();
                //cue.ContentTemplate = this.Resources["ApplicationDragTemplate"] as DataTemplate;
                cue.Content = box.SelectedItem;
                e.Options.DragCue = cue;
                e.Options.ArrowCue = RadDragAndDropManager.GenerateArrowCue();
            }
        }

        protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
        {
            base.PrepareContainerForItemOverride(element, item);
            RadDragAndDropManager.SetAllowDrag(element, true);
            RadDragAndDropManager.SetAllowDrop(element, true);
        }

        protected override void ClearContainerForItemOverride(DependencyObject element, object item)
        {
            base.ClearContainerForItemOverride(element, item);
            RadDragAndDropManager.SetAllowDrag(element, false);
            RadDragAndDropManager.SetAllowDrop(element, false);
        }
    }

Here is the XAML

        <local:DraggableListBox x:Name="lboAvailableRules" Grid.Column="1" Grid.Row="4" Grid.RowSpan="3" Margin="8,8,30,8">
            <local:DraggableListBox.ItemContainerStyle>
                <Style TargetType="ListBoxItem">
                    <Setter Property="HorizontalAlignment" Value="Stretch"/>
                    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
                    <Setter Property="DragDrop:RadDragAndDropManager.AllowDrop" Value="True"/>
                    <Setter Property="DragDrop:RadDragAndDropManager.AllowDrag" Value="True"/>
                </Style>
            </local:DraggableListBox.ItemContainerStyle>
            <local:DraggableListBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding RuleName}" FontWeight="Bold" HorizontalAlignment="Left" />
                </DataTemplate>
            </local:DraggableListBox.ItemTemplate>
        </local:DraggableListBox>

        <local:DraggableListBox x:Name="lboSelectedRules" Margin="8,8,30,8" Grid.Column="3" Grid.Row="4" Grid.RowSpan="3">
            <local:DraggableListBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding RuleName}" HorizontalAlignment="Center" />
                </DataTemplate>
            </local:DraggableListBox.ItemTemplate>
        </local:DraggableListBox>

I can't seem to get it to work.

The listboxes are within a grid (as you can see from the XAML. Is that a problem?

Thanks in advance for any help.

[ankit]

What is your source for dragable list box.
Make sure you have source for both and It should be observable collection, not list.

See how you go.

[Charles]

Thanks, but that didn't work. Here is my "GetRulesCompleted" method which fires when the data is retrieved from the WCF service call.

        private ObservableCollection<RuleDTO> availableRules;
        private ObservableCollection<RuleDTO> selectedRules;

        public void GetRulesCompleted(object sender, GetRulesCompletedEventArgs e)
        {
            if (e.Error != null)
            {
                MessageBox.Show(e.Error.Message);
            }
            else
            {
                availableRules = new ObservableCollection<RuleDTO>();
                foreach (var dto in e.Result)
                {
                    availableRules.Add(dto);
                }

                lboAvailableRules.ItemsSource = availableRules;
                lboSelectedRules.ItemsSource = selectedRules;
            }

        }

I have defined two ObservableCollections of type RuleDTO. During the GetRulesCompleted call, I translate the returned List<RuleDTO> into a corresponding ObservableCollection. Then I set the ItemsSource of both listboxes. One to a populated ObservableCollection and the other to a null ObservableCollection. The lboAvailableRules listbox is the source of items to be dragged to the lboSelectedRules listbox.

Once again - the dragdrop events do not fire - I have break points in all of them.

[Pablo]

Can you try with this in the constructor?

RadDragAndDropManager.SetAllowDrag(this, true);  

[Charles]

Sorry, that didn't work either.

I have that call in the constructor for the user control and in the constructor for the "DraggableListBox". Nothing seems to work.

[Pablo]

This is your posted code:

public event EventHandler<DragDropQueryEventArgs> DragQuery

{

add

{

this.AddHandler(RadDragAndDropManager.DropQueryEvent, value);

}

remove

{

this.RemoveHandler(RadDragAndDropManager.DragQueryEvent, value);

}

}

try replacing by
 this.AddHandler(RadDragAndDropManager.DragQueryEvent, value);  

And here...

public DraggableListBox()

{

RadDragAndDropManager.SetAllowDrop(this, true);               RadDragAndDropManager.SetAllowDrag(this, true);

this.DragQuery += new EventHandler<DragDropQueryEventArgs>(OnDragQuery);

this.DragInfo += new EventHandler<DragDropEventArgs>(OnDragInfo);

this.DropQuery += new EventHandler<DragDropQueryEventArgs>(OnDropQuery);

this.DropInfo += new EventHandler<DragDropEventArgs>(OnDropInfo);

}

[Charles]

Thanks very much, Pablo.

That did it.  I thought I had copied code directly from the sample - but I must have missed something.

I had a small logic problem after that with the ItemsSource of the receiving listbox being null, but I fixed that and it works fine.

Thanks again.