C# ado.net 使用task和await(四)

 1     class Program
 2     {
 3         private static string constr = "server=.;database=northwnd;integrated security=sspi";
 4         static void Main(string[] args)
 5         {
 6             Console.WriteLine("Running tasks...");
 7
 8             MethodTimer.TimeMethod(() =>
 9             {
10                 var t1 = GetEmployeeCount();
11                 var t2 = GetOrderCount();
12
13                 Task.WaitAll(t1, t2);
14                 Console.WriteLine("Number of employes: {0}, Number of orders: {1}", t1.Result, t2.Result);
15             }, 1, "Getting data took {1}ms");
16         }
17         public static async Task GetEandO()
18         {
19             int e =await GetEmployeeCount();
20             int o = await GetOrderCount();
21
22             Console.WriteLine("Number of employes: {0}, Number of orders: {1}", e, o);
23         }
24
25         public async static Task<int> GetEmployeeCount()
26         {
27             using (SqlConnection con=new SqlConnection(constr) )
28             {
29                 SqlCommand cmd = new SqlCommand("WaitFor Delay ‘0:0:02‘;select count(*) from employees", con);
30                 con.Open();
31                 return await cmd.ExecuteScalarAsync().ContinueWith(t => Convert.ToInt32(t.Result));
32             }
33         }
34         public async static Task<int> GetOrderCount()
35         {
36             using (SqlConnection conn = new SqlConnection(constr))
37             {
38                 SqlCommand cmd = new SqlCommand("WAITFOR DELAY ‘0:0:02‘;select count(*) from orders", conn);
39                 conn.Open();
40
41                 return await cmd.ExecuteScalarAsync().ContinueWith(t => Convert.ToInt32(t.Result));
42             }
43         }
44     }
45     public class MethodTimer
46     {
47         public static void TimeMethod(Action method, int iterations, string message)
48         {
49             Stopwatch sw = Stopwatch.StartNew();
50
51             for (int i = 0; i < iterations; i++)
52                 method();
53
54             sw.Stop();
55
56             Console.WriteLine(message, iterations, sw.ElapsedMilliseconds);
57         }
58     }