Watching Asynchronous Operation Execution Status

A tutorial example is provided on how to query the 'Status' property to watch the execution status of an asynchronous operation. The tutorial example shows 5 asynchronous operations running in 5 child threads.

In order to demonstrate the asynchronously of the GetStringAsync() method from the HttpClient class, I wrote another tutorial example program, MultipleAsyncTasks.cs, that starts 5 GetStringAsync() calls and watches their progresses:

// MultipleAsyncTasks.cs
// Copyright (c) 2015, HerongYang.com, All Rights Reserved.

using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
public class MultipleAsyncTasks {
   static void Main() {
      string[] sites = new string[5];
      sites[0] = "http://www.herongyang.com/Service/Hello_REST.php";
      sites[1] = "http://www.microsoft.com";
      sites[2] = "http://www.google.com";
      sites[3] = "http://www.faceboot.com";
      sites[4] = "http://www.twitter.com";

      // Launch 5 asynchronous tasks
      HttpClient c = new HttpClient();
      Task<string>[] tasks = new Task<string>[5];
      for (int i=0; i<5; i++) {
         tasks[i] = c.GetStringAsync(sites[i]);
      }

      // Watch their progresses
      bool wait = true;
      int w = 0;
      Console.WriteLine("Time, herongyang.com, microsft.com,"
         +" google.com, facebook, twitter.com");
      while (wait && w<=10000) {
         wait = false;
         string msg = "" + w;
         for (int i=0; i<5; i++) {
            TaskStatus s = tasks[i].Status;
            wait = wait || (s!=TaskStatus.RanToCompletion);
            msg = msg+", "+tasks[i].Status;
         }
         Console.WriteLine(msg);
         int t = 100;
         Thread.Sleep(t);
         w += t;
      }
   } 
}

Execution output is list below with .NET Framework 4.6.1 SDK:

C:\herong>%NET%\csc "/r:%REF%/System.Net.Http.dll" 
   MultipleAsyncTasks.cs
Microsoft (R) Visual C# Compiler version 4.6.1055.0
for C# 5

C:\herong>MultipleAsyncTasks
Time, herongyang.com, microsft.com, google.com, facebook, twitter.com
0, WaitingForActivation (WFA), WFA, WFA, WFA, WFA
100, WFA, WFA, WFA, WFA, WFA
200, WFA, WFA, WFA, WFA, WFA
300, WFA, WFA, WFA, WFA, WFA
400, RanToCompletion (RTC), WFA, WFA, WFA, WFA
500, RTC, RTC, WFA, WFA, WFA
600, RTC, RTC, WFA, WFA, WFA
700, RTC, RTC, WFA, WFA, WFA
800, RTC, RTC, WFA, WFA, WFA
900, RTC, RTC, RTC, WFA, WFA
1000, RTC, RTC, RTC, WFA, WFA
1100, RTC, RTC, RTC, WFA, WFA
1200, RTC, RTC, RTC, WFA, WFA
1300, RTC, RTC, RTC, WFA, WFA
1400, RTC, RTC, RTC, WFA, WFA
1500, RTC, RTC, RTC, WFA, WFA
1600, RTC, RTC, RTC, WFA, WFA
1700, RTC, RTC, RTC, WFA, WFA
1800, RTC, RTC, RTC, RTC, WFA
1900, RTC, RTC, RTC, RTC, WFA
2000, RTC, RTC, RTC, RTC, WFA
...
4800, RTC, RTC, RTC, RTC, WFA
4900, RTC, RTC, RTC, RTC, RTC

Excellent! Now we can see asynchronous operation in "slow" motion. Interesting notes about this example program:

Last update: 2015.

Table of Contents

 About This Book

 Introduction of C# (C Sharp)

 Data Type and Variables

 Logical Expressions and Conditional Statements

 Arrays and Loop Statements

 Data Type Features

 Floating-Point Data Types

 Passing Parameters to Methods

 Execution Environment Class

 Visual C# 2010 Express Edition

 Class Features

 C# Compiler and Intermediate Language

 Compiling C# Source Code Files

 MSBuild - Microsoft Build Engine

 Memory Usages of Processes

 Multithreading in C#

Async Feature from C# 5

 What Is Async Feature?

 GetStringAsync() Method in HttpClient Class

 GetStringAsync() Method Example Program

Watching Asynchronous Operation Execution Status

 "await" Expression and Child Thread

 "await" Expression Thread Example

 "async" Function Example

 System.IO.FileInfo Class

 System.Diagnostics.FileVersionInfo Class

 WPF - Windows Presentation Foundation

 Partial Classes and Partial Methods

 Outdated Tutorials

 References

 PDF Printing Version