XAMDataGrid: Dragging rows within grid

Question

I'm using the XamDataGrid v14.2 and want to add the feature of dragging and dropping rows within the datagrid.

I've looked thru the Infragistics forum posts, but most of the code samples show dragging and dropping rows from one grid to another.

Is it possible to drag and drop rows within the same grid? The effect that I want to achieve is to move the sequence of the Web Announcement row numbers.

Here is an image of how the grid looks:

Answer 1

I posted a sample with a behavior a few months ago on the Infragistics Forums that reorders rows that it similar to your requirement.

Relevant markup:

<igDP:XamDataGrid DataSource="{Binding Items}" IsSynchronizedWithCurrentItem="True" GroupByAreaLocation="None">
    <i:Interaction.Behaviors>
        <DragGrid:XamDataGridDragDropBehavior/>
    </i:Interaction.Behaviors>
</igDP:XamDataGrid>

C# code for the Behavior:

using System;
using System.Collections.Generic;
using Infragistics.Windows.DataPresenter;
using System.Windows.Interactivity;
using System.Windows;
using Infragistics.DragDrop;
using System.Windows.Input;
using Infragistics.Windows;
using System.Collections;
using System.Windows.Media;
using System.Reflection;

namespace DragGrid
{
    public class XamDataGridDragDropBehavior : Behavior<DataPresenterBase>
    {
        private DataPresenterBase dataPresenter;

        protected override void OnAttached()
        {
            base.OnAttached();
            dataPresenter = this.AssociatedObject;
            EventManager.RegisterClassHandler(typeof(XamDataGrid), UIElement.MouseLeftButtonDownEvent, new MouseButtonEventHandler(XamDataGrid_MouseLeftButtonDown));
            var dataPresenterStyle = new Style(typeof(DataRecordPresenter));
            dataPresenterStyle.Setters.Add(new EventSetter(FrameworkElement.LoadedEvent, new RoutedEventHandler(OnRecordPresenterLoaded)));
            dataPresenter.Resources.Add(typeof(DataRecordPresenter), dataPresenterStyle);
            DropTarget dropTarget = new DropTarget() { IsDropTarget = true };
            DragDropManager.SetDropTarget(dataPresenter, dropTarget);
        }

        private void OnRecordPresenterLoaded(object sender, RoutedEventArgs e)
        {

            var recordPresenter = sender as DataRecordPresenter;

            if (DragDropManager.GetDragSource(recordPresenter) != null)
            {
                return;
            }

            var dragSource = new DragSource
            {
                IsDraggable = true
            };

            dragSource.DragStart += new System.EventHandler<DragDropStartEventArgs>(dragSource_DragStart);
            dragSource.Drop += OnRecordDragDrop;
            dragSource.DragTemplate = ((Window)Utilities.GetAncestorFromType(this.dataPresenter, typeof(Window), true)).Resources["dragTemplate"] as DataTemplate;

            DragDropManager.SetDragSource(recordPresenter, dragSource);
        }

        void dragSource_DragStart(object sender, DragDropStartEventArgs e)
        {
            ArrayList draggedItems = new ArrayList();
            List<IList> sourceList = new List<IList>();
            SelectedRecordCollection selectedRecords = this.dataPresenter.SelectedItems.Records;
            DataRecord lastSelectedDataRecord = null;
            foreach (Record r in selectedRecords)
            {
                DataRecord dr = r as DataRecord;
                if (dr != null)
                {
                    lastSelectedDataRecord = dr;
                    draggedItems.Add(dr.DataItem);
                    sourceList.Add(GetSourceList(dr));
                }
            }
            DraggingData data = new DraggingData();
            data.Items = draggedItems;
            data.Lists = sourceList;
            if (lastSelectedDataRecord != null && lastSelectedDataRecord.ParentRecord != null)
            {
                data.SourceProperty = lastSelectedDataRecord.RecordManager.Field.Name;
            }
            e.Data = data;
        }

        private IList GetSourceList(DataRecord record)
        {
            IList retVal = null;
            DataRecord parent = record.ParentDataRecord;
            if (parent == null)
            {
                // There is no parent, use the grids list
                retVal = this.dataPresenter.DataSource as IList;
            }
            else
            {
                object parentDataItem = parent.DataItem;
                Type dataItemType = parentDataItem.GetType();
                PropertyInfo listProperty = dataItemType.GetProperty(record.RecordManager.Field.Name);
                retVal = listProperty.GetValue(parentDataItem, null) as IList;
            }
            return retVal;
        }

        private void OnRecordDragDrop(object sender, DropEventArgs dragInfo)
        {
            var result = VisualTreeHelper.HitTest(dragInfo.DropTarget, dragInfo.GetPosition(dragInfo.DropTarget));
            var targetElement = Utilities.GetAncestorFromType(result.VisualHit, typeof(DataRecordPresenter), true) as DataRecordPresenter;
            if (targetElement != null)
            {
                DataRecord targetRecord = targetElement.DataRecord;
                IList targetList = GetSourceList(targetRecord);
                object targetItem = targetRecord.DataItem;
                Type targetType = targetItem.GetType();
                DraggingData draggedData = dragInfo.Data as DraggingData;
                if (draggedData != null)
                {
                    IList itemsList = draggedData.Items;
                    object firstItem = itemsList[0];
                    IList<IList> listsList = draggedData.Lists;
                    if (!targetType.IsInstanceOfType(firstItem))
                    {
                        // the target type doesn't match the items we are dropping, get the child list from the parent if we have a property.
                        if (draggedData.SourceProperty != null)
                        {
                            PropertyInfo listProperty = targetType.GetProperty(draggedData.SourceProperty);
                            targetList = listProperty.GetValue(targetItem, null) as IList;
                            if (targetList != null)
                            {
                                for (int i = itemsList.Count - 1; i >= 0; i--)
                                {
                                    object currentItem = itemsList[i];
                                    int targetIndex = targetList.IndexOf(targetItem);
                                    listsList[i].Remove(currentItem);
                                    targetList.Add(currentItem);
                                }
                            }
                        }
                        else
                        {
                            MessageBox.Show("Can't drop here");
                        }
                    }
                    else
                    {
                        for (int i = itemsList.Count - 1; i >= 0; i--)
                        {
                            object currentItem = itemsList[i];
                            int targetIndex = targetList.IndexOf(targetItem);
                            listsList[i].Remove(currentItem);
                            targetList.Insert(targetIndex, currentItem);
                        }
                    }
                }

            }
        }

        void XamDataGrid_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            if (this.dataPresenter.Equals(sender))
            {
                DataRecordPresenter drp = Utilities.GetAncestorFromType(e.OriginalSource as DependencyObject, typeof(DataRecordPresenter), true) as DataRecordPresenter;
                if (drp != null)
                {
                    // If we already have a selection then we don't want the Grids SelectionController to be called which will cause a capture of the mouse and prevent dragging.
                    if (drp.IsSelected)
                    {
                        e.Handled = true;
                    }
                }
            }
        }

    }
}