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);
         }
     }