问题
我有两个 ListView。一个选项可以拖入另一个选项。这是“字段”ListView。另一个是“builder” ListView。我想不出一种方法来直观地向用户展示项目将被插入的位置。我想在 ListViewItem 之间画一条线以在视觉上帮助用户。
private void builder_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Move;
}
private void fields_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Move;
}
private void fields_ItemDrag(object sender, ItemDragEventArgs e)
{
fromBuilder = false;
fields.DoDragDrop(e.Item, DragDropEffects.Move);
}
private void builder_ItemDrag(object sender, ItemDragEventArgs e)
{
fromBuilder = true;
builder.DoDragDrop(e.Item, DragDropEffects.Move);
}
private void builderAndFields_DragDrop(object sender, DragEventArgs e)
{
ListViewItem i = new ListViewItem();
i = e.Data.GetData(typeof(ListViewItem)) as ListViewItem;
// Since this function works for both the builder and the fields,
// we have to check to see where we are dropping, the sender
// is the ListView we are dropping onto
if (sender.Equals(builder))
{
ListViewItem c = new ListViewItem();
c = (ListViewItem)i.Clone();
Point cp = builder.PointToClient(new Point(e.X, e.Y));
Console.WriteLine("cp: " + cp);
ListViewItem dragToItem = builder.GetItemAt(cp.X, cp.Y);
Console.WriteLine("dragToItem: " + dragToItem);
int dropIndex = dragToItem.Index;
// Now, we have to check to see if we are reordering or adding
// So, we check the flag to see if the dragDrop was initiated
// on the builder or on the fields ListView
if (fromBuilder)
{
builder.Items.Insert(dropIndex, c);
builder.Items.Remove(i);
}
else
{
Console.WriteLine(dropIndex);
builder.Items.Insert(dropIndex, c);
}
}
// If the sender is the fields listView, the user is trying to remove
// the item from the builder.
else
{
builder.Items.Remove(i);
}
}
