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1 | | -# How to drag and drop rows in wpf and uwp between listview and treegrid? |
| 1 | +# How to Drag and Drop Rows in WPF / UWP between ListView and TreeGrid? |
2 | 2 |
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3 | | -This example illustrates how to drag and drop rows in wpf and uwp between listview and treegrid. |
| 3 | +This example illustrates how to drag and drop rows between [WPF TreeGrid](https://www.syncfusion.com/wpf-controls/treegrid) / [UWP TreeGrid](https://www.syncfusion.com/uwp-ui-controls/treegrid) (SfTreeGrid) and listview. |
4 | 4 |
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5 | 5 | You can drag the item from ListView and drop into TreeGrid by overriding the [GetDropPosition](https://help.syncfusion.com/cr/uwp/Syncfusion.UI.Xaml.TreeGrid.TreeGridRowDragDropController.html#Syncfusion_UI_Xaml_TreeGrid_TreeGridRowDragDropController_GetDropPosition_Windows_UI_Xaml_DragEventArgs_Syncfusion_UI_Xaml_ScrollAxis_RowColumnIndex_), [ProcessOnDragOver](https://help.syncfusion.com/cr/uwp/Syncfusion.UI.Xaml.TreeGrid.TreeGridRowDragDropController.html#Syncfusion_UI_Xaml_TreeGrid_TreeGridRowDragDropController_ProcessOnDragOver_Windows_UI_Xaml_DragEventArgs_Syncfusion_UI_Xaml_ScrollAxis_RowColumnIndex_), and [ProcessOnDrop](https://help.syncfusion.com/cr/uwp/Syncfusion.UI.Xaml.TreeGrid.TreeGridRowDragDropController.html#Syncfusion_UI_Xaml_TreeGrid_TreeGridRowDragDropController_ProcessOnDrop_Windows_UI_Xaml_DragEventArgs_Syncfusion_UI_Xaml_ScrollAxis_RowColumnIndex_) methods in the [TreeGridRowDragDropController](https://help.syncfusion.com/cr/uwp/Syncfusion.UI.Xaml.TreeGrid.TreeGridRowDragDropController.html) class. |
6 | 6 |
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7 | | -In ListView, use the `DragItemsStarting` event and add dragged item. After dropping in TreeGrid, the dragged item is added to TreeGrid based on the dropped position. |
| 7 | +In ListView, use the **DragItemsStarting** event and add dragged item. |
| 8 | + |
| 9 | +``` csharp |
| 10 | +listView.CanDragItems = true; |
| 11 | +listView.DragItemsStarting += ListView_DragItemsStarting; |
| 12 | +listView.DragItemsCompleted += ListView_DragItemsCompleted; |
| 13 | + |
| 14 | +private void ListView_DragItemsStarting(object sender, DragItemsStartingEventArgs e) |
| 15 | +{ |
| 16 | + e.Data.Properties.Add("DraggedItem", listView.SelectedItem); |
| 17 | + e.Data.SetText(StandardDataFormats.Text); |
| 18 | +} |
| 19 | + |
| 20 | +private void ListView_DragItemsCompleted(ListViewBase sender, DragItemsCompletedEventArgs args) |
| 21 | +{ |
| 22 | + foreach (var item in args.Items) |
| 23 | + { |
| 24 | + (listView.ItemsSource as ObservableCollection<PersonInfo>).Remove(item as PersonInfo); |
| 25 | + } |
| 26 | +} |
| 27 | +``` |
| 28 | + |
| 29 | +``` csharp |
| 30 | +public class TreeGridRowDragDropControllerExt : TreeGridRowDragDropController |
| 31 | +{ |
| 32 | + |
| 33 | + public TreeGridRowDragDropControllerExt(SfTreeGrid treeGrid) : base(treeGrid) |
| 34 | + { |
| 35 | + } |
| 36 | + |
| 37 | + protected override void ProcessOnDrop(DragEventArgs args, RowColumnIndex rowColumnIndex) |
| 38 | + { |
| 39 | + this.TreeGrid.AutoScroller.AutoScrolling = AutoScrollOrientation.None; |
| 40 | + var dropPosition = GetDropPosition(args, rowColumnIndex); |
| 41 | + |
| 42 | + if (dropPosition != DropPosition.None && rowColumnIndex.RowIndex != -1) |
| 43 | + { |
| 44 | + var draggedItem = GetDraggedItem(args); |
| 45 | + |
| 46 | + if (this.TreeGrid.View is TreeGridNestedView) |
| 47 | + { |
| 48 | + var treeNode = this.TreeGrid.GetNodeAtRowIndex(rowColumnIndex.RowIndex); |
| 49 | + |
| 50 | + if (treeNode == null) |
| 51 | + return; |
| 52 | + var data = treeNode.Item; |
| 53 | + TreeGrid.SelectionController.SuspendUpdates(); |
| 54 | + var itemIndex = -1; |
| 55 | + |
| 56 | + TreeNode parentNode = null; |
| 57 | + |
| 58 | + if (dropPosition == DropPosition.DropBelow || dropPosition == DropPosition.DropAbove) |
| 59 | + parentNode = treeNode.ParentNode; |
| 60 | + else if (dropPosition == DropPosition.DropAsChild) |
| 61 | + { |
| 62 | + if (!treeNode.IsExpanded) |
| 63 | + TreeGrid.ExpandNode(treeNode); |
| 64 | + parentNode = treeNode; |
| 65 | + } |
| 66 | + IList sourceCollection = null; |
| 67 | + |
| 68 | + if (dropPosition == DropPosition.DropBelow || dropPosition == DropPosition.DropAbove) |
| 69 | + { |
| 70 | + |
| 71 | + if (treeNode.ParentNode != null) |
| 72 | + { |
| 73 | + var collection = TreeGrid.View.GetPropertyAccessProvider().GetValue(treeNode.ParentNode.Item, TreeGrid.ChildPropertyName) as IEnumerable; |
| 74 | + sourceCollection = GetSourceListCollection(collection); |
| 75 | + } |
| 76 | + else |
| 77 | + { |
| 78 | + sourceCollection = GetSourceListCollection(TreeGrid.View.SourceCollection); |
| 79 | + } |
| 80 | + |
| 81 | + itemIndex = sourceCollection.IndexOf(data); |
| 82 | + |
| 83 | + if (dropPosition == DropPosition.DropBelow) |
| 84 | + { |
| 85 | + itemIndex += 1; |
| 86 | + } |
| 87 | + } |
| 88 | + else if (dropPosition == DropPosition.DropAsChild) |
| 89 | + { |
| 90 | + var collection = TreeGrid.View.GetPropertyAccessProvider().GetValue(data, TreeGrid.ChildPropertyName) as IEnumerable; |
| 91 | + sourceCollection = GetSourceListCollection(collection); |
| 92 | + |
| 93 | + if (sourceCollection == null) |
| 94 | + { |
| 95 | + var list = data.GetType().GetProperty(TreeGrid.ChildPropertyName).PropertyType.CreateNew() as IList; |
| 96 | + |
| 97 | + if (list != null) |
| 98 | + { |
| 99 | + TreeGrid.View.GetPropertyAccessProvider().SetValue(treeNode.Item, TreeGrid.ChildPropertyName, list); |
| 100 | + sourceCollection = list; |
| 101 | + } |
| 102 | + } |
| 103 | + itemIndex = sourceCollection.Count; |
| 104 | + } |
| 105 | + sourceCollection.Insert(itemIndex, draggedItem); |
| 106 | + TreeGrid.SelectionController.ResumeUpdates(); |
| 107 | + (TreeGrid.SelectionController as TreeGridRowSelectionController).RefreshSelection(); |
| 108 | + } |
| 109 | + } |
| 110 | + CloseDragIndicators(); |
| 111 | + } |
| 112 | + |
| 113 | + protected override DropPosition GetDropPosition(DragEventArgs args, RowColumnIndex rowColumnIndex) |
| 114 | + { |
| 115 | + bool canDrop = true; |
| 116 | + var p = args.GetPosition(this.TreeGrid); |
| 117 | + var treeNode = this.TreeGrid.GetNodeAtRowIndex(rowColumnIndex.RowIndex); |
| 118 | + ScrollAxisRegion columnRegion = ScrollAxisRegion.Body; |
| 119 | + var treeGridPanel = TreeGrid.GetTreePanel(); |
| 120 | + |
| 121 | + if (treeGridPanel.FrozenColumns > 0) |
| 122 | + columnRegion = ScrollAxisRegion.Header; |
| 123 | + var rowRect = treeGridPanel.RangeToRect(ScrollAxisRegion.Body, columnRegion, rowColumnIndex, true, false); |
| 124 | + var node = treeNode; |
| 125 | + |
| 126 | + if (!canDrop) |
| 127 | + return DropPosition.None; |
| 128 | + else if (p.Y > rowRect.Y + 15 && p.Y < rowRect.Y + 35) |
| 129 | + { |
| 130 | + return DropPosition.DropAsChild; |
| 131 | + } |
| 132 | + else if (p.Y < rowRect.Y + 15) |
| 133 | + { |
| 134 | + return DropPosition.DropAbove; |
| 135 | + } |
| 136 | + else if (p.Y > rowRect.Y + 35) |
| 137 | + { |
| 138 | + return DropPosition.DropBelow; |
| 139 | + } |
| 140 | + else |
| 141 | + return DropPosition.Default; |
| 142 | + } |
| 143 | + |
| 144 | + protected override void ProcessOnDragOver(DragEventArgs args, RowColumnIndex rowColumnIndex) |
| 145 | + { |
| 146 | + autoExpandNode = null; |
| 147 | + var node = this.TreeGrid.GetNodeAtRowIndex(rowColumnIndex.RowIndex); |
| 148 | + var draggedItem = GetDraggedItem(args); |
| 149 | + var dropPosition = GetDropPosition(args, rowColumnIndex); |
| 150 | + |
| 151 | + if (draggedItem == null) |
| 152 | + return; |
| 153 | + |
| 154 | + if (dropPosition == DropPosition.None || dropPosition == DropPosition.Default) |
| 155 | + { |
| 156 | + CloseDragIndicators(); |
| 157 | + args.AcceptedOperation = DataPackageOperation.None; |
| 158 | + args.DragUIOverride.Caption = "Can't drop here"; |
| 159 | + return; |
| 160 | + } |
| 161 | + else if (dropPosition == DropPosition.DropAbove) |
| 162 | + { |
| 163 | + args.DragUIOverride.Caption = "Drop above"; |
| 164 | + } |
| 165 | + else if (dropPosition == DropPosition.DropAsChild) |
| 166 | + { |
| 167 | + args.DragUIOverride.Caption = "Drop as child"; |
| 168 | + } |
| 169 | + else |
| 170 | + { |
| 171 | + args.DragUIOverride.Caption = "Drop below"; |
| 172 | + } |
| 173 | + args.AcceptedOperation = DataPackageOperation.Move; |
| 174 | + ShowDragIndicators(dropPosition, rowColumnIndex); |
| 175 | + args.Handled = true; |
| 176 | + } |
| 177 | + |
| 178 | + private object GetDraggedItem(DragEventArgs dragEventArgs) |
| 179 | + { |
| 180 | + if (dragEventArgs.DataView.Properties.ContainsKey("DraggedItem")) |
| 181 | + return dragEventArgs.DataView.Properties["DraggedItem"]; |
| 182 | + else |
| 183 | + return null; |
| 184 | + } |
| 185 | + |
| 186 | + internal IList GetSourceListCollection(IEnumerable collection = null) |
| 187 | + { |
| 188 | + IList list = null; |
| 189 | + |
| 190 | + if (collection == null) |
| 191 | + collection = TreeGrid.View.SourceCollection; |
| 192 | + |
| 193 | + if ((collection as IList) != null) |
| 194 | + { |
| 195 | + list = collection as IList; |
| 196 | + } |
| 197 | + return list; |
| 198 | + } |
| 199 | +} |
| 200 | +``` |
| 201 | + |
| 202 | +After dropping in TreeGrid, the dragged item is added to TreeGrid based on the dropped position. |
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