{
            for (int i = 1; i <=500; i++)
            {
                ThreadPool.QueueUserWorkItem(Execute, i + 1);
            }
        }
void Execute(Object obj)
        {
             int thread = (int)obj;
            try
            {
                using (TestEntities ctx = new TestEntities())
                {
                    int i = 1;
                    foreach (var v in ctx.Customers)
                    {
                        Thread.Sleep(i * 1000);
                        i++;
                    }
                }
                listBox1.Items.Add("Thread " + thread.ToString() + " End Success ");
            }
            catch (Exception e)
            {
                listBox1.Items.Add("Thread " + thread.ToString() + " Error :" + e.Message);
            }
        }