C# async

I/O should use async, asynchronous method can be achieved:

message, delegate, multi-threading

Thread-safe

1.	private void button_Click(object sender, EventArgs e)
2.	      {
3.	          var task = new Task(() =>
4.	          {
5.	              this.lblResult.Invoke(new Action (() => {
6.	                  this.lblResult.Text = DateTime.Now.ToLongTimeString();
7.	              }));
8.	          });
9.	          task.Start();
10.	      }

Before async/await

1.	      private void button_Click(object sender, EventArgs e)
2.	      {
3.	          this.lblResult.Text = "starting to ...";
4.	          var compute = new Func<int, string>(i =>
5.	          {
6.	              long result = 1;
7.
8.	              for (int n = 0; n <= i; n++)
9.	              {
10.	                  result += 1;
11.	              }
12.
13.	              return result.ToString();
14.	          });
15.
16.	          compute.BeginInvoke(int.MaxValue / 2, new AsyncCallback(ar =>
17.	          {
18.	              #region
21.	              //this.lblResult.Text = compute.EndInvoke(ar);
22.	              #endregion
23.
24.	              this.lblResult.Invoke(new MethodInvoker(() =>
25.	                  this.lblResult.Text = compute.EndInvoke(ar)));
26.	          }
27.	          ), new object());
28.	      }

After aync/await

1.	   public long DoSomething(int n)
2.	   {
3.	       long result = 1;
4.
5.	       for (int i = 0; i <= n; i++)
6.	       {
7.	           result += 1;
8.	       }
9.
10.	       return result;
11.	   } 

12.	   private async void button_Click(object sender, EventArgs e)
13.	   {
14.	       this.lblResult.Text = "staring to ...";
15.	       var value = await DoSomethingAsync(int.MaxValue / 2);
16.	       this.lblResult.Text = value.ToString();
17.	   } 

18.	   private Task<long> DoSomethingAsync(int n)
19.	   {
20.	       return Task.Run<long>(() => DoSomething(n));
21.	   }