private void list_DragOver(object sender, DragEventArgs e)
{
if (dragData == null)
{
return;
}
Point cp = list.PointToClient(new Point(e.X, e.Y));
ListViewItem dragToItem = list.GetItemAt(10, cp.Y);
if (dragToItem == null)
{
return;
}
DragEventData.DragEventTargetMode mode =
((cp.Y > (dragToItem.Bounds.Top + dragToItem.Bounds.Height / 2)) ?
DragEventData.DragEventTargetMode.insertAfter :
DragEventData.DragEventTargetMode.insertBefore);
if (dragData.DragToItem == dragToItem &&
dragData.Mode == mode)
{
return;
}
using (System.Drawing.Graphics gr = System.Drawing.Graphics.FromHwnd(list.Handle))
{
if (dragData.DragToItem != null)
{
DragEventData.DrawMoveLine(gr, list.BackColor, dragData.DragToItem.Bounds, dragData.Mode);
}
DragEventData.DrawMoveLine(gr, Color.Red, dragToItem.Bounds, mode);
}
dragData.DragToItem = dragToItem;
dragData.Mode = mode;
}
private void list_DragDrop(object sender, DragEventArgs e)
{
try
{
if (dragData == null)
{
return;
}
ListViewItem[] sel = null;
if (e.Effect == DragDropEffects.Move &&
dragData.DragToItem != null &&
list.SelectedItems.Count != 0)
{
//Obtain the index of the item at the mouse pointer.
sel = new ListViewItem[list.SelectedItems.Count];
for (int i = 0; i <= list.SelectedItems.Count - 1; i++)
{
sel[i] = list.SelectedItems[i];
}
}
if (sel == null)
{
return;
}
int counter = 0;
foreach (ListViewItem selItem in sel)
{
if (selItem == dragData.DragToItem)
{
continue;
}
if (list.Items.Contains(selItem))
{
list.Items.Remove(selItem);
}
int dragIndex = dragData.DragToItem.Index;
switch (dragData.Mode)
{
case DragEventData.DragEventTargetMode.insertBefore:
list.Items.Insert(dragIndex, selItem);
break;
case DragEventData.DragEventTargetMode.insertAfter:
list.Items.Insert(dragIndex + 1 + counter++, selItem);
break;
}
}
if (AfterLegendOrdering != null)
{
AfterLegendOrdering(this, new EventArgs());
}
}
finally
{
if (dragData != null && dragData.DragToItem != null)
{
using (System.Drawing.Graphics gr = System.Drawing.Graphics.FromHwnd(list.Handle))
{
DragEventData.DrawMoveLine(
gr, list.BackColor, dragData.DragToItem.Bounds, dragData.Mode);
}
}
dragData = null;
}
}