[Solved] Drag & drop without remove element.

[Marcin]

I have implemented drag&drop like in your example (RadTreeView -> ListBox). This is working but I want not remove element from RTV. Can you help me? Where is the mistake?
Thanks.

MainPage.xaml

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
    xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
    xmlns:dragDrop="clr-namespace:Telerik.Windows.Controls.DragDrop;assembly=Telerik.Windows.Controls"
    xmlns:primitives="clr-namespace:Telerik.Windows.Controls.Primitives;assembly=Telerik.Windows.Controls"
    xmlns:example="clr-namespace:InSEAAtr"
    x:Class="InSEAAtr.MainPage"
    mc:Ignorable="d"
    d:DesignHeight="600" d:DesignWidth="800">
    <UserControl.Resources>

        <LinearGradientBrush x:Key="DropPossibleBackground" StartPoint="0 0" EndPoint="0 1">
            <GradientStop Offset="0" Color="White" />
            <GradientStop Offset="1" Color="#FFE699" />
        </LinearGradientBrush>

        <telerik:HierarchicalDataTemplate x:Key="CategoryTemplate" ItemsSource="{Binding Items}">
            <StackPanel Orientation="Horizontal">
                <Image Width="16" Height="16" Source="Images/Icons/AtrValidate16.png"
    Margin="3" VerticalAlignment="Center" />
                <TextBlock Text="{Binding Title}" Margin="2" VerticalAlignment="Center" />
            </StackPanel>
        </telerik:HierarchicalDataTemplate>

        <DataTemplate x:Name="ProductTemplate">
            <telerik:RadDockPanel Margin="2" MaxWidth="200">
                <TextBlock Text="{Binding Name}" FontWeight="Bold" telerik:RadDockPanel.Dock="Top" />
                <TextBlock Text="{Binding UnitPrice}" Foreground="Green" telerik:RadDockPanel.Dock="Left" />
                <TextBlock Text="{Binding Description}" telerik:RadDockPanel.Dock="Left" Margin="2 0 0 0" Foreground="Gray" TextWrapping="Wrap" />
            </telerik:RadDockPanel>
        </DataTemplate>

        <DataTemplate x:Name="MenuTemplate">
            <telerik:RadDockPanel Margin="2" MaxWidth="200">
                <TextBlock Text="{Binding Name}" FontWeight="Bold" telerik:RadDockPanel.Dock="Top" />
                <TextBlock Text="{Binding Count}" telerik:RadDockPanel.Dock="Left" />
            </telerik:RadDockPanel>
        </DataTemplate>

        <example:ExampleTemplateSelector x:Key="ExampleTemplateSelector"
                  CategoryTemplate="{StaticResource CategoryTemplate}"
                  ProductTemplate="{StaticResource ProductTemplate}"
                  MenuTemplate="{StaticResource MenuTemplate}"/>

    </UserControl.Resources>



    <Grid x:Name="LayoutRoot" >
        <Grid.RowDefinitions>
            <RowDefinition Height="30"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <Border Grid.Row="0">
            <Border.Background>
                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="#FF828282" Offset="0"/>
                    <GradientStop Color="#FF585858" Offset="1"/>
                    <GradientStop Color="#FF4D4D4D" Offset="0.41"/>
                    <GradientStop Color="#FF232323" Offset="0.431"/>
                    <GradientStop Color="#FF151515" Offset="0.452"/>
                    <GradientStop Color="#FF1B1B1B" Offset="0.469"/>
                </LinearGradientBrush>
            </Border.Background>
        </Border>
        <StackPanel HorizontalAlignment="Left" Margin="4,4,0,4" Orientation="Horizontal"  d:LayoutOverrides="Height">
            <telerik:RadButton x:Name="but3" Content="" Margin="0,0,5,0" Width="22"/>
            <telerik:RadButton x:Name="but4" Content="" Margin="0,0,5,0" Width="22"/>
            <telerik:RadButton x:Name="but1" Content="" Margin="0,0,5,0" Width="22"/>
            <telerik:RadButton x:Name="but2" Content="" Margin="0,0,0,0" Width="22"/>
        </StackPanel>

        <StackPanel x:Name="spZalogowany" HorizontalAlignment="Center" Margin="0,7" Orientation="Horizontal">
            <sdk:Label x:Name="labLogowanie" d:LayoutOverrides="Height" Foreground="White" Content="Zalogowano: "/>
            <sdk:Label x:Name="labUser" d:LayoutOverrides="Height" Foreground="White" Content="" ToolTipService.ToolTip="Zalogowany użytkownik"/>
        </StackPanel>
        <telerik:RadButton x:Name="butWyloguj" Content="Wyloguj" HorizontalAlignment="Right" Margin="0,4,8,4" d:LayoutOverrides="Height"/>

        <Border Grid.Row="1" Height="30" VerticalAlignment="Top">
            <Border.Background>
                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="#FF828282" Offset="0"/>
                    <GradientStop Color="#FF585858" Offset="1"/>
                    <GradientStop Color="#FF4D4D4D" Offset="0.41"/>
                    <GradientStop Color="#FF232323" Offset="0.431"/>
                    <GradientStop Color="#FF151515" Offset="0.452"/>
                    <GradientStop Color="#FF1B1B1B" Offset="0.469"/>
                </LinearGradientBrush>
            </Border.Background>
        </Border>

        <telerik:RadDocking Margin="0,30,0,0" Grid.Row="1" d:LayoutOverrides="Width, Height">
            <telerik:RadDocking.DocumentHost>
                <telerik:RadSplitContainer>
                    <telerik:RadPaneGroup>
                        <telerik:RadPane x:Name="rpGrid" Header="Dokumenty" CanUserClose="False">
                            <telerik:RadGridView/>
                        </telerik:RadPane>
                    </telerik:RadPaneGroup>
                </telerik:RadSplitContainer>
            </telerik:RadDocking.DocumentHost>
            <telerik:RadSplitContainer>
                <telerik:RadPaneGroup SelectedIndex="0">
                    <telerik:RadPane x:Name="rpDrzewo" Header="Menu" CanUserClose="False">
                        <telerik:RadTreeView x:Name="rtvDokumenty" IsLineEnabled="True"
                                             IsDragDropEnabled="True" ItemTemplateSelector="{StaticResource ExampleTemplateSelector}">
                            <Style TargetType="telerik:RadTreeViewItem">
                                <Setter Property="IsExpanded" Value="True" />
                            </Style>

                        </telerik:RadTreeView>
                    </telerik:RadPane>

                    <telerik:RadPane x:Name="rpSkroty" Header="Moje dokumenty" CanUserClose="False">
                        <ListBox x:Name="lbSkroty" dragDrop:RadDragAndDropManager.AllowDrop="True">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <StackPanel Orientation="Vertical" HorizontalAlignment="Center" Width="100">

                                        <Image Source="{Binding Icon}" HorizontalAlignment="Center" Width="16" Height="16"/>
                                        <TextBlock Text="{Binding Name}" FontWeight="Bold"  HorizontalAlignment="Center"
                                                   TextWrapping="Wrap"/>
                                        <TextBlock Text="{Binding Count}"  HorizontalAlignment="Center"
                                                   TextWrapping="Wrap"/>
                                    </StackPanel>
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                            <ListBox.Style>
                                <Style TargetType="ListBox">
                                    <Setter Property="dragDrop:RadDragAndDropManager.AllowDrop" Value="True" />
                                </Style>
                            </ListBox.Style>
                            <ListBox.ItemContainerStyle>
                                <Style TargetType="Control">

                                    <Setter Property="dragDrop:RadDragAndDropManager.AllowDrop" Value="True" />
                                </Style>
                            </ListBox.ItemContainerStyle>
                            <ListBox.ItemsPanel>
                                <ItemsPanelTemplate>
                                    <primitives:RadUniformGrid HorizontalAlignment="Center" VerticalAlignment="Top" Columns="1"/>
                                </ItemsPanelTemplate>
                            </ListBox.ItemsPanel>
                        </ListBox>
                    </telerik:RadPane>

                </telerik:RadPaneGroup>
            </telerik:RadSplitContainer>
            <telerik:RadSplitContainer InitialPosition="DockedBottom">
                <telerik:RadPaneGroup SelectedIndex="-1">
                    <telerik:RadPane Header="Pozycja obiegu" x:Name="rpObieg" CanUserClose="False"/>
                </telerik:RadPaneGroup>
            </telerik:RadSplitContainer>
        </telerik:RadDocking>


    </Grid>
</UserControl>

MainPage.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using Telerik.Windows.Controls;
using Telerik.Windows.Controls.DragDrop;
using Telerik.Windows.Controls.TreeView;
using Telerik.Windows.Controls.Primitives;

namespace InSEAAtr
{
    public partial class MainPage : UserControl
    {
        //ObservableCollection<RadTreeViewItem> allMenu = Generate();
        ObservableCollection<RadTreeViewItem> myMenu;

        public MainPage()
        {
            InitializeComponent();

            rtvDokumenty.Items.Clear();
            rtvDokumenty.ItemsSource = CategoryViewModel.Generate();



            IList orderSource = new ObservableCollection<MenuViewModel>();

            lbSkroty.ItemsSource = orderSource;


            RadDragAndDropManager.AddDropQueryHandler(lbSkroty, OnDropQuery);
            RadDragAndDropManager.AddDropInfoHandler(lbSkroty, OnDropInfo);
            RadDragAndDropManager.AddDragQueryHandler(lbSkroty, OnDragQuery);
            RadDragAndDropManager.AddDragInfoHandler(lbSkroty, OnDragInfo);

            //demo!



        }

         #region demo
        // OnDragQuery event handler
        private void OnDragQuery(object sender, DragDropQueryEventArgs e)
        {
            System.Windows.Controls.ListBox listBox = sender as System.Windows.Controls.ListBox;

            if (listBox != null)
            {
                IList selectedItems = listBox.SelectedItems.Cast<object>().ToList();
                e.Options.Payload = selectedItems;
            }
            e.QueryResult = true;
            e.Handled = true;
        }
        // OnDropQuery event handler
        private void OnDropQuery(object sender, DragDropQueryEventArgs e)
        {
            ICollection draggedItems = e.Options.Payload as ICollection;
            bool result = draggedItems.Cast<object>().All((object item) => item is MenuViewModel);
            e.QueryResult = result;
            e.Handled = true;
        }
        // OnDragInfo event handler
        private void OnDragInfo(object sender, DragDropEventArgs e)
        {
            System.Windows.Controls.ListBox listBox = sender as System.Windows.Controls.ListBox;
            IEnumerable draggedItems = e.Options.Payload as IEnumerable;
            if (e.Options.Status == DragStatus.DragInProgress)
            {
                //Set up a drag cue:
                TreeViewDragCue cue = new TreeViewDragCue();
                cue.ItemTemplate = listBox.ItemTemplate;
                cue.ItemsSource = draggedItems;
                e.Options.DragCue = cue;
            }
            else if (e.Options.Status == DragStatus.DragComplete)
            {
                IList source = listBox.ItemsSource as IList;
                foreach (object draggedItem in draggedItems)
                {
                    //source.Remove(draggedItem);
                }
            }
        }
        // OnDropInfo event handler
        private void OnDropInfo(object sender, DragDropEventArgs e)
        {
            System.Windows.Controls.ItemsControl wishlist = e.Options.Destination as System.Windows.Controls.ItemsControl;
            ICollection draggedItems = e.Options.Payload as ICollection;
            if (wishlist == null)
                return;
            // Get the drag cu that the TreeView or we have created
            TreeViewDragCue cue = e.Options.DragCue as TreeViewDragCue;
            if (e.Options.Status == DragStatus.DropPossible)
            {
                // Set a suitable text:
                cue.DragActionContent = String.Format("Dodaj do Moich Dokumentów");
                cue.IsDropPossible = true;
                wishlist.Background = this.Resources["DropPossibleBackground"] as Brush;
            }
            else if (e.Options.Status == DragStatus.DropImpossible)
            {
                cue.DragActionContent = null;
                cue.IsDropPossible = false;
            }
            else if (e.Options.Status == DragStatus.DropComplete)
            {
                IList items = wishlist.ItemsSource as IList;
                foreach (object draggedItem in draggedItems)
                {
                    items.Add(draggedItem);
                }


            }
            if (e.Options.Status != DragStatus.DropPossible)
            {
                wishlist.Background = new SolidColorBrush(Colors.White);
            }
        }



        #endregion

    }



    public class CategoryViewModel
    {
        public static IList Generate()
        {
            CategoryViewModel fak = new CategoryViewModel();
            fak.Title = "Faktury";
            foreach (MenuViewModel item in MenuViewModel.Generate(1))
            {
                fak.Items.Add(item);
            }
            CategoryViewModel kor = new CategoryViewModel();
            kor.Title = "Korespondencja";
            foreach (MenuViewModel item in MenuViewModel.Generate(2))
            {
                kor.Items.Add(item);
            }
            return new ObservableCollection<object>()
             {
              fak, kor
             };
        }
        public CategoryViewModel()
        {
            Items = new ObservableCollection<object>();
        }
        public string Title
        {
            get;
            set;
        }
        public IList Items
        {
            get;
            set;
        }
    }

    public class ProductViewModel
    {
        // Data generation.
        private static Random generator = new Random(1676545846);
        private static string[] adjectives = "Fabulous,Amazing,New,Classic,Modern,Durable,Outstanding,Excellent,Premium".Split(',');
        private static string[] owner = "Alaska,Jonhn,Ray,Ruby,Stone,Lilly,Scott,Barney,Dorian,Neo,Sarah".Split(',');
        private static string[] objects = "Pen,Manual,Bicycle,Umbrella,Mouse,Vase,Keyboard".Split(',');
        private static decimal[] prices = { 12.99M, 13.15M, 24.99M, 33.99M, 9.99M, 15.99M, 16.99M, 12.50M };
        public static IEnumerable<ProductViewModel> Generate(int count)
        {
            for (int i = 0; i < count; i++)
            {
                string product = objects[generator.Next(objects.Length)];
                ProductViewModel result = new ProductViewModel();
                result.Name = String.Format("{0}'s {1} {2}",
                        owner[generator.Next(owner.Length)],
                        adjectives[generator.Next(adjectives.Length)],
                        product);
                result.UnitPrice = prices[generator.Next(prices.Length)];
                result.Description = String.Format("Exquisite handcrafted {0}.", product.ToLower());
                yield return result;
            }
        }
        public string Name
        {
            get;
            set;
        }
        public string Description
        {
            get;
            set;
        }
        public decimal UnitPrice
        {
            get;
            set;
        }
    }

    public class MenuViewModel
    {
        public static List<MenuViewModel> Generate(int count)
        {

            List<MenuViewModel> result = new List<MenuViewModel>();

            switch (count)
            {
                case 1:
                    MenuViewModel m2 = new MenuViewModel();
                    m2.Count = 2;
                    m2.Name = "Korespondencja przychodząca";
                    m2.Icon = "Images/Icons/AtrValidate16.png";
                    result.Add(m2);

                    MenuViewModel m3 = new MenuViewModel();
                    m3.Count = 2;
                    m3.Name = "Korespondencja wychodząca";
                    m3.Icon = "Images/Icons/BUzytkownikUsun16.png";
                    result.Add(m3);

                    break;
                case 2:


                    MenuViewModel m6 = new MenuViewModel();
                    m6.Count = 6;
                    m6.Name = "Faktury kosztowe";
                    m6.Icon = "Images/Icons/BUzytkownikEdytuj16.png";
                    result.Add(m6);

                    MenuViewModel m1 = new MenuViewModel();
                    m1.Count = 6;
                    m1.Name = "Faktury kosztowe";
                    m1.Icon = "Images/Icons/BUzytkownikHaslo16.png";
                    result.Add(m1);

                    MenuViewModel m4 = new MenuViewModel();
                    m4.Count = 2;
                    m4.Name = "Faktury drobne";
                    m4.Icon = "Images/Icons/BUzytkownikNieaktywni16.png";
                    result.Add(m4);
                    break;
                default:
                    break;

            }
            return result;
        }

        public string Name
        {
            get;
            set;
        }

        public int Count
        {
            get;
            set;
        }

        public string Icon
        {
            get;
            set;
        }
    }

    public class ExampleTemplateSelector : Telerik.Windows.Controls.DataTemplateSelector
    {
        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
            if (item is ProductViewModel)
                return ProductTemplate;
            else if (item is CategoryViewModel)
                return CategoryTemplate;
            else if (item is MenuViewModel)
                return MenuTemplate;
            return null;
        }
        public DataTemplate ProductTemplate
        {
            get;
            set;
        }
        public DataTemplate CategoryTemplate
        {
            get;
            set;
        }

        public DataTemplate MenuTemplate
        {
            get;
            set;
        }
    }
}

[Tina Stancheva]

Hello Marcin,

You can handle the PreviewDragEnded event (set e.Handled  = true for its event args) and this will mean that the RadTreeView will not modify its collections.

private void treeView_PreviewDragEnded(object sender, RadTreeViewDragEndedEventArgs e)
{
    e.Handled = true;
}

Give this a try and let me know if it works for you or if you need more info.

Kind regards,
Tina Stancheva
the Telerik team

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[Marcin]

Thank you, Tina

Kind regards,
Marcin

[Hans]

I have the same problem, But I want my dragged TreeViewItem to move when dropped inside the treeview.
But when I drag it into a RichTextBox, I just want to know what kind of item is dropped into the richTextBox.
And the item inside the TreeView to stay in place.

With this solution its either don't do anything at all or always get moved.
And in the RadTreeViewDragEndedEventArgs I can't find anything that refers to the RichTextBox.
So I can't tell where its dropped within this event.

[Tsvyatko]

Hello Hans,

 You might want to modify this code as follows:

private void RadTreeView_PreviewDragEnded(object sender, Telerik.Windows.Controls.RadTreeViewDragEndedEventArgs e)
{
    e.Handled = RadDragAndDropManager.Options.Destination != sender;
}

Regards,
Tsvyatko
the Telerik team

[loowool]

Dear telerik,

I have a similar situation, but I followed the steps of the demo found in ScheduleView.SilverLight/DragDrop from a ListBox to a ScheduleView. I'd like to Clone the Item in the ListView to the ScheduleView NOT REMOVE IT. How do I do that?

Thanks as always.
Salah A. Malaeb

[Valeri Hristov]

Hi,

Unfortunately this behavior cannot be easily changed, if possible at all. It appears that RadScheduleView automatically removes the dragged items from the source and we do not provide API to override this. We are working on such changes, but they will not be included in the upcoming SP1 this week. Currently you need to hold Ctrl while releasing the mouse button to copy the appointments.

All the best,
Valeri Hristov
the Telerik team

[Tarcisis]

Are you able to open the dialog (appointmentEdit) when you drop the element into ScheduleView?

[Andrew]

How can I disable the 'remove dragged item from drag source' with the DragDropManager? The PreviewDragEnded event is deprecated and appears not to be hit. Thanks.

[Kalin]

Hi Andrew,

Can you please share some more details on the exact controls you are using and how the drag drop functionality is implemented (some sample code or project would be helpful)? 

I'm looking forward to hearing from you.

Regards,
Kalin
Telerik

[Andrew]

Thanks for the reply. I managed to find my error, I was using a mix of the old and new Drag Drop methodologies - moving fully to the DragDropManager solved the issue. Thanks again.

[Kalin]

Hi Andrew,

I'm glad you have managed to resolve the issue. If you have any other questions or concerns, please let us know.

Regards,
Kalin
Telerik