listbox 消息显示系统

    
调用消息系统
  private delegate void ListBoxDelegate(ListBox control, string xstr);
        private void ListBox_InvokeRequired(ListBox control, string xstr)
        {
            if (control.InvokeRequired)          
            {
                ListBoxDelegate mydelegate = new ListBoxDelegate(ListBox_InvokeRequired);
                control.Invoke(mydelegate, new object[] { control, xstr });
            }
            else
            {
                if (control.Items.Count > 1000)
                {
                    control.Items.Clear();
                }
                control.Items.Add(xstr);
                control.SelectedIndex = control.Items.Count - 1;
                control.SelectedIndex = -1;
            }
        }

  ListBox_InvokeRequired(listBox1, DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + "    " + sb.ToString());