C# ado.net 使用task和await(四)

    class Program
    {
        private static string constr = "server=.;database=northwnd;integrated security=sspi";
        static void Main(string[] args)
        {
            Console.WriteLine("Running tasks...");

            MethodTimer.TimeMethod(() =>
            {
                var t1 = GetEmployeeCount();
                var t2 = GetOrderCount();

                Task.WaitAll(t1, t2);
                Console.WriteLine("Number of employes: {0}, Number of orders: {1}", t1.Result, t2.Result);
            }, 1, "Getting data took {1}ms");
        }
        public static async Task GetEandO()
        {
            int e =await GetEmployeeCount();
            int o = await GetOrderCount();

            Console.WriteLine("Number of employes: {0}, Number of orders: {1}", e, o);
        }

        public async static Task<int> GetEmployeeCount()
        {
            using (SqlConnection con=new SqlConnection(constr) )
            {
                SqlCommand cmd = new SqlCommand("WaitFor Delay '0:0:02';select count(*) from employees", con);
                con.Open();
                return await cmd.ExecuteScalarAsync().ContinueWith(t => Convert.ToInt32(t.Result));
            }
        }
        public async static Task<int> GetOrderCount()
        {
            using (SqlConnection conn = new SqlConnection(constr))
            {
                SqlCommand cmd = new SqlCommand("WAITFOR DELAY '0:0:02';select count(*) from orders", conn);
                conn.Open();

                return await cmd.ExecuteScalarAsync().ContinueWith(t => Convert.ToInt32(t.Result));
            }
        } 
    }
    public class MethodTimer
    {
        public static void TimeMethod(Action method, int iterations, string message)
        {
            Stopwatch sw = Stopwatch.StartNew();

            for (int i = 0; i < iterations; i++)
                method();

            sw.Stop();

            Console.WriteLine(message, iterations, sw.ElapsedMilliseconds);
        }
    }