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.	   }