Devexpress将文件从资源管理器移动到TreeList

Question

I'm trying to drag & drop files into my TreeList . I'm able to move files/folders which are inside the TreeList , but I also want to drag files from Windows Explorer into the folders of my TreeList . The dragdrop event of the treeList is triggered but both nodes (dragged and target) are null. e.Data is not null for both nodes, e.Data is a DataObject . Maybe there's something wrong with the conversion to TreeList nodes, but this event works for drag & drop insde the TreeList . How can I solve the nodes problem?

This is the code snippet where the problem occurs:

     private void treeList1_DragDrop(object sender, DragEventArgs e)
    {

        var draggedNode = e.Data.GetData(typeof(TreeListNode)) as TreeListNode; //null        
        var targetNode = Tree.ViewInfo.GetHitTest(Tree.PointToClient(new Point(e.X, e.Y))).Node; // null

        if (targetNode == null) return;

        if (draggedNode != null)
        {
            if (targetNode[treeListColumn3].ToString() == "File")
            {
                if (targetNode.ParentNode == draggedNode.ParentNode)
                    return;
                MoveInFolder(draggedNode, targetNode.ParentNode);
            }
            else
            {
                MoveInFolder(draggedNode, targetNode);
            }
            e.Effect = DragDropEffects.None;
        }
        else
        {
            string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);

            if (files == null) return;

            //Do something with your TreeList
            var nodeTarget = Tree.ViewInfo.GetHitTest(Tree.PointToClient(new Point(e.X, e.Y))).Node;
            TreeListNode node;
            FileInfo fi;
            foreach (string s in files)
            {

                fi = new FileInfo(s);
                node = Tree.AppendNode(new object[] { s, fi.Name, "File", fi.Length, fi }, nodeTarget);
                node.HasChildren = false;
                MoveInFolder(node, nodeTarget);
            }
        }

EDIT I editted my code to the code which works for me.

Answer 1

When you drag files from Windows Explorer you cannot convert it to TreeListNode object because you are draging object of another type. You can only get the array of your files by using DataFormats.FileDrop as parameter for e.Data.GetData method and create/move/delete nodes in your TreeList according to files that you droped to it:

private void treeList1_DragDrop(object sender, DragEventArgs e)
{
    var draggedNode = e.Data.GetData(typeof(TreeListNode)) as TreeListNode; //null        
    var targetNode = Tree.ViewInfo.GetHitTest(Tree.PointToClient(new Point(e.X, e.Y))).Node; // null

    if (targetNode == null) return;

    if (draggedNode != null)
    {
        if (targetNode[treeListColumn3].ToString() == "File")
        {
            if (targetNode.ParentNode == draggedNode.ParentNode)
                return;
            MoveInFolder(draggedNode, targetNode.ParentNode);
        }
        else
        {
            MoveInFolder(draggedNode, targetNode);
        }
        e.Effect = DragDropEffects.None;            
    }
    else
    {
        string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);

        if (files == null) return;

        //Do something with your TreeList
    }
}