Moving Nodes

[Sl1ver]

I've got a problem, i got the nodes to move but
1. they copy nodes(if you drag it to 3 different places it will actually have 3 of the same nodes)
2. i want to make the nodes, if moved update the new nodes locations

This is my coding

 private void tvDescriptions_MouseDown(object sender, MouseEventArgs e)
        {
            TreeView tree = (TreeView)sender;
 
            // Get the node underneath the mouse.
            TreeNode node = tree.GetNodeAt(e.X, e.Y);
 
            // Start the drag-and-drop operation with a cloned copy of the node.
            if (node != null)
            {
                tree.DoDragDrop(node.Clone(), DragDropEffects.Copy);
            }
        }
 
        private void tvDescriptions_DragOver(object sender, DragEventArgs e)
        {
            // Get the tree.
            TreeView tree = (TreeView)sender;
 
            // Drag and drop denied by default.
            e.Effect = DragDropEffects.None;
 
            // Is it a valid format?
            if (e.Data.GetData(typeof(TreeNode)) != null)
            {
                // Get the screen point.
                Point pt = new Point(e.X, e.Y);
 
                // Convert to a point in the TreeView's coordinate system.
                pt = tree.PointToClient(pt);
 
                // Is the mouse over a valid node?
                TreeNode node = tree.GetNodeAt(pt);
                if (node != null)
                {
                    e.Effect = DragDropEffects.Copy;
                    tree.SelectedNode = node;
                }
            }
        }
 
        private void tvDescriptions_DragDrop(object sender, DragEventArgs e)
        {
            // Get the tree.
            TreeView tree = (TreeView)sender;
 
            // Get the screen point.
            Point pt = new Point(e.X, e.Y);
 
            // Convert to a point in the TreeView's coordinate system.
            pt = tree.PointToClient(pt);
 
            // Get the node underneath the mouse.
            TreeNode node = tree.GetNodeAt(pt);
 
            // Add a child node.
            node.Nodes.Add((TreeNode)e.Data.GetData(typeof(TreeNode)));
 
            // Show the newly added node if it is not already visible.
            node.Expand();
        }
 
        private void tvDescriptions_ItemDrag(object sender, ItemDragEventArgs e)
        {
 
        }
 

[tlhintoq]

So you want a 'move' not a copy? Am I reading that right?
Do the copy, then at the node where you moved it from perform a .Remove

At line 6 you learn which node is being copied (naming it 'node')
between lines 11 and 12 add... tree.Nodes.Remo ve(node);

[Sl1ver]

Thanx, you really know your stuff. How or where will i post a event to update the database with the new information?

[tlhintoq]

where will i post a event to update the database with the new information?

I don't know your program as well as you do, so I can only give you a generic answer... I would raise and event to perform an update after I'm done with all my changes. Where that fits into what you've engineered, only you know. This treeview could be on its own user control, or it could be on a floating pallet or it could be in the middle of your one and only form. I can't say. But that's the beauty of events... As long as you have another class 'listening' (subscribed) to the event it will still work.

[Sl1ver]

Hi,

this is my coding. I get a error that states "Must use a updatable query" and if you double click on the nodes the whole program freezes. any help?

 private void tvLocations_MouseDown(object sender, MouseEventArgs e)
        {
            TreeView tree = (TreeView)sender;
 
            // Get the node underneath the mouse.
            TreeNode node = tree.GetNodeAt(e.X, e.Y);
 
            // Start the drag-and-drop operation with a cloned copy of the node.
            if (node != null)
            {
                tree.DoDragDrop(node, DragDropEffects.Copy);
                //node.Remove();
 
            }
        }
 
        private void tvLocations_DragOver(object sender, DragEventArgs e)
        {
            // Get the tree.
            TreeView tree = (TreeView)sender;
 
 
            // Drag and drop denied by default.
            e.Effect = DragDropEffects.None;
 
            // Is it a valid format?
            if (e.Data.GetData(typeof(TreeNode)) != null)
            {
                // Get the screen point.
                Point pt = new Point(e.X, e.Y);
 
                // Convert to a point in the TreeView's coordinate system.
                pt = tree.PointToClient(pt);
 
                // Is the mouse over a valid node?
                TreeNode node = tree.GetNodeAt(pt);
                if (node != null)
                {
                    e.Effect = DragDropEffects.Copy;
                    tree.SelectedNode = node;
 
                }
            }
        }
 
        private void tvLocations_DragDrop(object sender, DragEventArgs e)
        {
            try
            {
                // Get the tree.
                TreeView tree = (TreeView)sender;
 
                tree.BeginUpdate();
 
                // Get the screen point.
                Point pt = new Point(e.X, e.Y);
 
                // Convert to a point in the TreeView's coordinate system.
                pt = tree.PointToClient(pt);
 
                // Get the node underneath the mouse.
                TreeNode node = tree.GetNodeAt(pt);
 
                TreeNode childNode = (TreeNode)e.Data.GetData(typeof(TreeNode));
 
                // Remoce this node
                tree.Nodes.Remove(childNode);
 
                // Add the node to the new parent
                node.Nodes.Add(childNode);
 
                // Show the newly added node if it is not already visible.
                node.Expand();
 
                tree.EndUpdate();
 
                UpdateDBStructure(childNode.Tag, node.Tag);
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error: " + ex.Message);
            }
        }
 
        private void tvLocations_ItemDrag(object sender, ItemDragEventArgs e)
        {
 
        }
 
        private void UpdateDBStructure(object Id, object parentId)
        {                        
            OleDbConnection mConn = new OleDbConnection(strCon);
 
            mConn.Open();            
 
            string UpdateStr = @"UPDATE qx_AssetLocation SET 
                                 alc__acl_id = " + parentId + 
                               " where alc__ID = " + Id;
 
            OleDbCommand myCmd = mConn.CreateCommand();
            myCmd.CommandText = UpdateStr;
            try
            {
                myCmd.ExecuteNonQuery();
                //MessageBox.Show("Data added to database");
 
            }
            catch (Exception ed)
            {
                MessageBox.Show("Error: " + ed.Message, "Error");
            }
            finally
            {
                myCmd.Dispose();
                mConn.Close();
                mConn.Dispose();
                tvLocations.Nodes.Clear();
                //PopulateTree();
            }
 
 
        }

[tlhintoq]

Put a breakpoint in your UpdateDbStructu re (line 92 or so) and walk through it one step at a time with F-10. See if that helps you find the exact location and nature of the issue.

[Sl1ver]

thanx man for the help, things are working