textbox - wait for user to finish typing in a Text Box

private void txtBusinessName_TextChanged(object sender, EventArgs e)
{
            TimerKey = 3000;
            timer1.Interval = TimerKey;
            timer1.Enabled = true;
}

private void timer1_Tick(object sender, EventArgs e)
{
          SearchFirstTextbox();
            timer1.Enabled = false;
}

public void SearchFirstTextbox()
{
           string searchList = "<sreacn Key Word>";
            int col = 1;
            int colCount = col + 1;

            for (int lvelist = 0; lvelist < listview1.Items.Count; lvelist++)
            {
                if (listview1.Items[lvelist].Text.ToLower().Contains(searchList.ToLower()))
                {
                    listview1.TopItem = lvwClientInformation.Items[lvelist];
                    listview1.Items[lvelist].Selected = true;
                    listview1.Select();
                    lvelist = listview1.Items.Count;
                }
}