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295
Problem with Code to do Drag and Drop
posted

 I have copied a method from on this forum of how to enable items to be dragged up and down a list view. Which works well problem is i also have another function which is called on doubleclick of an item but it seems the mouse dragging events cancel out my double click

Can anyone see where i am going wrong?

 Drage Procs...

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         private void listView_MouseDown(object sender, MouseEventArgs e)
        {
            //  Record the cursor location
            if (e.Button == MouseButtons.Left)
            { this.lastMouseDown = e.Location; }
            else
            { this.lastMouseDown = null; }
        }

        private void listView_MouseMove(object sender, MouseEventArgs e)
        {
            UltraListView listView = sender as UltraListView;


            //  If the mouse has moved outside the area in which it was pressed,
            //  start a drag operation
            if (this.lastMouseDown.HasValue)
            {
                Size dragSize = SystemInformation.DragSize;
                Rectangle dragRect = new Rectangle(this.lastMouseDown.Value, dragSize);
                dragRect.X -= dragSize.Width / 2;
                dragRect.Y -= dragSize.Height / 2;

                if (dragRect.Contains(e.Location))
                {
                    UltraListViewItem itemAtPoint = listView.ItemFromPoint(e.Location);

                    if (itemAtPoint != null)
                    {
                        this.lastMouseDown = null;
                        this.dragItem = itemAtPoint;
                        listView.DoDragDrop(this.dragItem, DragDropEffects.Move);
                    }
                }
            }
        }

        private void listView_QueryContinueDrag(object sender, QueryContinueDragEventArgs e)
        {
            UltraListView listView = sender as UltraListView;

            //  Cancel the drag operation if the escape key was pressed
            if (e.EscapePressed)
            {
                this.OnDragEnd(listView, true);
                e.Action = DragAction.Cancel;
            }
        }

        private void listView_DragOver(object sender, DragEventArgs e)
        {
            UltraListView listView = sender as UltraListView;
            Point clientPos = listView.PointToClient(new Point(e.X, e.Y));

            if (this.dragItem != null)
            {
                this.dropItem = listView.ItemFromPoint(clientPos);

                e.Effect = this.dropItem != null && this.dropItem != this.dragItem ? DragDropEffects.Move : DragDropEffects.None;
            }

            //  TODO: This could be improved with a hover timer

            //  If the cursor is within {dragScrollAreaHeight} pixels
            //  of the top or bottom edges of the control, scroll
            int dragScrollAreaHeight = 8;

            Rectangle displayRect = listView.DisplayRectangle;
            Rectangle topScrollArea = displayRect;
            topScrollArea.Height = (dragScrollAreaHeight * 2);

            Rectangle bottomScrollArea = displayRect;
            bottomScrollArea.Y = bottomScrollArea.Bottom - dragScrollAreaHeight;
            bottomScrollArea.Height = dragScrollAreaHeight;

            ISelectionManager selectionManager = listView as ISelectionManager;
            if (topScrollArea.Contains(clientPos) || bottomScrollArea.Contains(clientPos))
            { selectionManager.DoDragScrollVertical(0); }
        }

        private void listView_DragDrop(object sender, DragEventArgs e)
        {
            UltraListView listView = sender as UltraListView;
            this.OnDragEnd(listView, false);
        }

        private void OnDragEnd(UltraListView listView, bool canceled)
        {
            if (canceled == false && this.dragItem != null && this.dropItem != null)
            {
                listView.BeginUpdate();

                listView.Items.Remove(this.dragItem);
                int index = this.dropItem.Index + 1;
                listView.Items.Insert(index, this.dragItem);

                listView.EndUpdate();
            }

            this.dragItem = this.dropItem = null;
            this.lastMouseDown = null;
        }

 

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event handlers added in form constructor

--------------------------------------------------------------------------- 

 

this.uListSelected.AllowDrop = true;

this.uListSelected.MouseDown += new MouseEventHandler(listView_MouseDown);

this.uListSelected.MouseMove += new MouseEventHandler(listView_MouseMove);
            this.uListSelected.DragOver += new DragEventHandler(listView_DragOver);
            this.uListSelected.DragDrop += new DragEventHandler(listView_DragDrop);
            this.uListSelected.QueryContinueDrag += new QueryContinueDragEventHandler(listView_QueryContinueDrag);

 

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