TreeViewのノードをコードで直接設定している場合に、ドラッグ＆ドロップによって1つ目のTreeViewから他のTreeViewにノードをコピーするには、C1TreeViewのDragEnter、DragDrop、およびItemDragイベントを利用し、Add、Insertメソッドを用いてノードの追加、挿入を行う方法が考えられます。

以下に、左側のTreeViewから右側のTreeViewへノードをコピーするための簡単な実装例を記載します。



◎サンプルコード（VB）

Imports C1.Win.TreeView

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        C1TreeView1.AllowDrop = True
        C1TreeView2.AllowDrop = True

        For i As Integer = 0 To 4
            C1TreeView1.Nodes.Add("Node" & i)
            C1TreeView2.Nodes.Add("Node" & i * 100)

            For j As Integer = 0 To 4
                C1TreeView1.Nodes(i).Nodes.Add("Node" & (i * 10 + j))
                C1TreeView2.Nodes(i).Nodes.Add("Node" & (i * 100 + j))
            Next
        Next

        AddHandler C1TreeView1.ItemDrag, AddressOf C1TreeView_ItemDrag
        AddHandler C1TreeView2.ItemDrag, AddressOf C1TreeView_ItemDrag
        AddHandler C1TreeView1.DragEnter, AddressOf C1TreeView_DragEnter
        AddHandler C1TreeView2.DragEnter, AddressOf C1TreeView_DragEnter
        AddHandler C1TreeView1.DragDrop, AddressOf C1TreeView_DragDrop
        AddHandler C1TreeView2.DragDrop, AddressOf C1TreeView_DragDrop
    End Sub

    Private Sub C1TreeView_DragDrop(ByVal sender As Object, ByVal e As DragEventArgs)
        Dim distanceNodes = CType(e.Data.GetData(GetType(C1TreeNode())), C1TreeNode())
        Dim distanceNode = distanceNodes(0)
        Dim pos = CType(e.Data.GetData(GetType(DragDropPosition)), DragDropPosition)
        Dim c1CopiedNode = New C1TreeNode(distanceNode.GetValue())
        Dim treeView = CType(sender, C1TreeView)
        Dim p = treeView.PointToClient(New Point(e.X, e.Y))
        Dim currentNode = treeView.GetNodeAtPoint(p)

        If currentNode IsNot Nothing Then
            Dim index = currentNode.ParentCollection.IndexOf(currentNode)

            Select Case pos
                Case DragDropPosition.After
                    currentNode.ParentCollection.Insert(index + 1, c1CopiedNode)
                Case DragDropPosition.Before
                    currentNode.ParentCollection.Insert(index, c1CopiedNode)
                Case DragDropPosition.Inner
                    currentNode.Nodes.Add(c1CopiedNode)
            End Select
        Else
            treeView.Nodes.Add(c1CopiedNode)
        End If
    End Sub

    Private Sub C1TreeView_DragEnter(ByVal sender As Object, ByVal e As DragEventArgs)
        e.Effect = DragDropEffects.Move
    End Sub

    Private Sub C1TreeView_ItemDrag(ByVal sender As Object, ByVal e As C1.Win.TreeView.C1TreeViewItemDragEventArgs)
        DoDragDrop(e.DraggedData, DragDropEffects.Move)
    End Sub
End Class

◎サンプルコード（C#）

using C1.Win.TreeView;

namespace DragAndDrop
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            c1TreeView1.AllowDrop = true;
            c1TreeView2.AllowDrop = true;
            c1TreeView1.ItemDrag += C1TreeView_ItemDrag;
            c1TreeView2.ItemDrag += C1TreeView_ItemDrag;
            c1TreeView1.DragEnter += C1TreeView_DragEnter;
            c1TreeView2.DragEnter += C1TreeView_DragEnter;
            c1TreeView1.DragDrop += C1TreeView_DragDrop;
            c1TreeView2.DragDrop += C1TreeView_DragDrop;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            for (int i = 0; i < 5; i++)
            {
                c1TreeView1.Nodes.Add("Node" + i);
                c1TreeView2.Nodes.Add("Node" + i * 100);
                for (int j = 0; j < 5; j++)
                {
                    c1TreeView1.Nodes[i].Nodes.Add("Node" + (i * 10 + j));
                    c1TreeView2.Nodes[i].Nodes.Add("Node" + (i * 100 + j));
                }
            }
        }

        private void C1TreeView_DragDrop(object sender, DragEventArgs e)
        {
            // get dropped data
            var distanceNodes = (C1TreeNode[])e.Data.GetData(typeof(C1TreeNode[]));
            var distanceNode = distanceNodes[0];
            
            var pos = (DragDropPosition)e.Data.GetData(typeof(DragDropPosition));
            var c1CopiedNode = new C1TreeNode(distanceNode.GetValue());
            var treeView = (C1TreeView)sender;

            var p = treeView.PointToClient(new Point(e.X, e.Y));
            var currentNode = treeView.GetNodeAtPoint(p);
            if (currentNode != null)
            {
                var index = currentNode.ParentCollection.IndexOf(currentNode);

                switch (pos)
                {
                    case DragDropPosition.After:
                        currentNode.ParentCollection.Insert(index + 1, c1CopiedNode);
                        break;
                    case DragDropPosition.Before:
                        currentNode.ParentCollection.Insert(index, c1CopiedNode);
                        break;
                    case DragDropPosition.Inner:
                        currentNode.Nodes.Add(c1CopiedNode);
                        break;
                }
            }
            else // ツリーにノードがない場合
            {
                treeView.Nodes.Add(c1CopiedNode);
            }
        }

        private void C1TreeView_DragEnter(object sender, DragEventArgs e)
        {
            e.Effect = DragDropEffects.Move;
        }

        private void C1TreeView_ItemDrag(object sender, C1.Win.TreeView.C1TreeViewItemDragEventArgs e)
        {            
            DoDragDrop(e.DraggedData, DragDropEffects.Move);
        }
    }
}