GetStringAsync() Method Example Program

C# Tutorials - Herong's Tutorial Examples

∟GetStringAsync() Method Example Program

A tutorial example is provided on how to use GetStringAsync() method in the System.Net.Http.HttpClient class to send a GET request in a child thread as am asynchronous operation.

Here is my first tutorial example C# program, GetStringAsyncTest.cs, on asynchronous operation with GetStringAsync() method from the HttpClient class:

// GetStringAsyncTest.cs
// Copyright (c) 2016 HerongYang.com. All Rights Reserved.

using System;
using System.Net.Http;
using System.Threading.Tasks;
public class GetStringAsyncTest {
   static void Main() {
      string uri = "https://www.herongyang.com/Service/Hello_REST.php";
      HttpClient c = new HttpClient();
      Task<string> t = c.GetStringAsync(uri);
      string s = t.Result;
      Console.WriteLine(s);	
   }
}

If you compile and run it with .NET Framework 4.6.1 SDK, you will get:

C:\herong>set "NET=\windows\Microsoft.NET\Framework\v4.0.30319"
C:\herong>set "REF=C:\Program Files\Reference Assemblies\Microsoft
   \Framework\.NETFramework\v4.6.1"

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

C:\herong>GetStringAsyncTest.exe
<Result>
   <Message>
      Hello from server - herongyang.com.
   </Message>
</Result>

Cool. The example program works! Please note that:

When c.GetStringAsync(uri) was called, a child thread was launched to wait and retrieve the HTTP response.
When t.Result called, the main thread was put in wait mode until the child thread was done.
So the HTTP GET operation was executed asynchronously in the child thread. But the main thread did not take advantage to do any other work parallel to the child thread.
We also need to provide the reference .DLL file, System.Net.Http.dll, explicitly, when compiling HttpClient applications.