c# - 如何加速 Winforms ListView 项目删除？

Question

我已经使用了 listView.BeginUpdate() 和 listView.EndUpdate()，但是当我从 25k 中删除 100 个项目时，它仍然需要大约 10 秒。

有什么想法、技巧可以让它更快吗？

编辑:

this.listView.BeginUpdate();
for (int i = this.listView.CheckedItems.Count - 1; i > -1; --i)
{
    this.listView.CheckedItems[i].Remove();
}
this.listView.EndUpdate();

Answer 1

您可以从这里开始优化:

List<int> toRemove = new List<int>();

foreach (ListViewItem item in this.listView.Items)
{
    if (item.Checked) // check other remove conditions here
        toRemove.Add(item.Index);
}

/* sort indices descending, so you'll remove items with higher indices first
   and they will not be shifted when you remove items with lower indices */
toRemove.Sort((x, y) => y.CompareTo(x));
/* in this specific case you can simply use toRemove.Reverse(); 
   or iterate thru toRemove in reverse order
   because it is already sorted ascending.
   But you might want to force sort it descending in some other cases.
*/

this.listView.BeginUpdate();

foreach (int itemIndex in toRemove)
    this.listView.Items.RemoveAt(itemIndex); // use RemoveAt when possible. It's much faster with large collections

this.listView.EndUpdate();