private void button1_Click_1(object sender, EventArgs e)
{
ListBox.ObjectCollection list = PlayList.Items;
Random random = new Random();
int w = list.Count;
PlayList.BeginUpdate();
while (w > 1)
{
w--;
int u = random.Next(w + 1);
object value = list[u];
list[u] = list[w];
list[w] = value;
}
PlayList.EndUpdate();
PlayList.Invalidate();
}