Check all item in listview with huge list item?

Question

I want to check about 3000 item in listview. This is a bit of code :

foreach (ListViewItem item in this.lvItem.Items)
{
    item.Checked = !item.Ch         


        

Answer 1

for (int i = 0; i <= listView1.Items.Count - 1; i++)
{
     if (!listView1.Items[i].Checked)
     listView1.Items[i].Checked = true;
}