Multithreading vs. Asynchronous Programming in .Net Core
Tags: asynchronousprogram, multithread, dotnetcore, csharp
Published: 2023-02-19 19:11:55

In recent years, asynchronous programming has grown in popularity, particularly in .NET Core development. We will examine the distinctions between multithreading and asynchronous programming, as well as their advantages and disadvantages, in this blog post.

By executing many threads concurrently, multithreading enables concurrency in a software. The operating system schedules these threads, which all operate concurrently with one another. For managing tasks that are computationally demanding or I/O-bound, multithreading is an effective tool.

On the other side, asynchronous programming is a method for carrying out non-blocking I/O activities. The foundation of asynchronous programming is the callback idea, in which a function that handles I/O doesn’t block the thread that called it. Instead, the method releases the calling thread and executes a callback on a different thread after the task is finished.

Asynchronous programming is about concurrency, whereas multithreading is really about parallelism. Asynchronous programming does I/O operations without blocking, whereas multithreading runs several threads at once.

### Multithreading and Asynchronous Programming Pros and Cons

There are various advantages to multithreading, including:

* Improved performance:
Multithreading can help speed up the execution of computationally intensive tasks.

* Improved responsiveness:
Multithreading can help make the user interface more responsive, as long-running tasks are executed in the background.

However, there are a number of disadvantages to multithreading, including:

* Complexity: 
Multithreading adds complexity to a program, as threads need to be synchronized and coordinated to avoid race conditions and deadlocks.

* Resource usage: 
Multithreading can consume a significant amount of system resources, such as memory and CPU time.

Also there are various advantages to asynchronous programming, including:

* Improved scalability: 
Asynchronous programming allows a single thread to handle multiple I/O-bound operations, which can improve the scalability of a program.

* Improved responsiveness: 
Asynchronous programming can make the user interface more responsive, as the calling thread is not blocked by I/O-bound operations.

However, there are a number of disadvantages to asynchronous programming, including:

* Complexity: 
Asynchronous programming can add complexity to a program, as it requires the use of callbacks and other asynchronous programming techniques.

* Debugging: 
Asynchronous programming can be more difficult to debug, as the execution of code is split across multiple threads.

### When to Use Multithreading vs. Asynchronous Programming

The best uses for multithreading are computationally demanding, **parallelizable** tasks. Multithreading is advantageous in processes like image processing and numerical simulations, for instance.

Making web requests, interacting with other services, and other I/O-bound operations like reading from and writing to files or databases are ideally suited for asynchronous programming. When I/O-bound actions are carried out in the background while the user interface remains responsive, asynchronous programming can increase a program’s responsiveness.

### Examples of Multithreading and Asynchronous Programming in .NET Core

Let’s take a look at some examples of multithreading and asynchronous programming in .NET Core.

### Multithreading Example
```
using System;
using System.Threading;

class Program
{
	static void Main(string[] args)
	{
		Thread thread = new Thread(() => {
			// Perform a long-running task
			Thread.Sleep(1000);
			Console.WriteLine("Task complete");
		});
		thread.Start();
		Console.WriteLine("Thread started");
	}
}
```
In this example, we create a new thread and start it. The thread performs a long-running task (in this case; sleeping for one second) and then outputs a message.

### Asynchronous Programming Example

```
using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
	static async Task Main(string[] args)
	{
		HttpClient client = new HttpClient();
		HttpResponseMessage response = await client.GetAsync("https://www.example.com");
		string content = await response.Content.ReadAsStringAsync();
		Console.WriteLine(content);
	}
}
```
In this example, we create an instance of the HttpClient class and use it to make a web request to `https://www.example.com`. The `GetAsync` method returns a `Task<HttpResponseMessage>` that represents the asynchronous operation of making the request. We use the await keyword to wait for the operation to complete and get the `HttpResponseMessage` object.

Next, we use the `ReadAsStringAsync` method to read the content of the response as a string. Again, this method returns a `Task<string>` that represents the asynchronous operation of reading the response content. We use the `await` keyword to wait for the operation to complete and get the content as a string.

Finally, we output the content of the response to the console.

By using asynchronous programming, we can make a web request without blocking the calling thread. The `await` keyword allows the calling thread to continue executing other tasks, such as updating the user interface or handling user input.

### Conclusion

Asynchronous programming and multithreading are effective methods for attaining concurrency in.NET Core development. **Asynchronous programming** is better suited for I/O-bound jobs than **multithreading** is for computationally heavy tasks. The best technique for the job must be chosen because both offer advantages and disadvantages. I hope this article has clarified the distinctions between **asynchronous programming** and **multithreading** as well as when to use each.