How To Perform Drag-Drop Operations on TreeView Control in Windows Forms
Friends,
Drag/Drop functionality is a ease to end user in each and every technology and almost every user is comfortable using the drag-drop feature. In this post we will see how to perform drag and drop operation of nodes in a single TreeView control. There are few events that we will be working with. They are – ItemDrag(), DragEnter() and DragDrop(). Apart from these, we will also use some inbuilt functions that facilitate drag/drop operations on Windows forms. So, Let’s get started. To create a draggable/drop-ableĀ Treeview control on windows forms, we will use the steps mentioned below –
- Set the AllowDrop property of TreeView control to True.
- Populate the TreeView with some nodes. I am here filling the nodes with some sample data.
private function LoadData() { for (int i = 0; i < 5; i++) { TreeNode node = new TreeNode("Node " + i); for (int j = 0; j < 3; j++) { TreeNode n1 = new TreeNode("Sub-node :" + i + " - " + j); node.Nodes.Add(n1); } treeView1.Nodes.Add(node); } }
- Handle the ItemDrag() event handler of the TreeView and write the code below-
private void treeView1_ItemDrag(object sender, ItemDragEventArgs e) { DoDragDrop(e.Item, DragDropEffects.Move); }
- Handle the DragEnter() event handler of the TreeView and write the code below-
private void treeView1_DragEnter(object sender, ItemDragEventArgs e) { e.Effect = DragDropEffects.Move; }
- Handle the DragDrop() event handler of the TreeView and write the code below-
private void treeView1_DragDrop(object sender, ItemDragEventArgs e) { TreeNode NewNode; if (e.Data.GetDataPresent("System.Windows.Forms.TreeNode", false)) { Point pt = ((TreeView)sender).PointToClient(new Point(e.X, e.Y)); TreeNode DestinationNode = ((TreeView)sender).GetNodeAt(pt); NewNode = (TreeNode)e.Data.GetData("System.Windows.Forms.TreeNode"); DestinationNode.Nodes.Add((TreeNode)NewNode.Clone()); DestinationNode.Expand(); //Remove Original Node NewNode.Remove(); } }
- You’re done.
- Execute the application and try dragging/dropping the nodes on the TreeView control.
Keep learning and sharing! Cheers!