Asynchronous Programming

Asynchronous Programming in C#:

Asynchronous programming in C# allows you to perform long-running tasks without blocking the execution thread. This is particularly useful in scenarios like network operations, file I/O, or any operation that might take a significant amount of time.

1. Async and Await Keywords: The 'async' and 'await' are two keywords introduced in C# 5.0 to simplify asynchronous programming.

• async: This keyword is used to define a method as asynchronous. It doesn't necessarily mean the method will run asynchronously, but it allows the method to use the 'await' keyword.

• await: This keyword is used inside an async method to asynchronously wait for the completion of a task. It tells the compiler that the method should pause until the awaited task is complete, allowing the calling thread to continue executing other work.

2. Task and Task<T>: In asynchronous programming, you often work with the 'Task' class or its generic counterpart 'Task<T>'. A 'Task' represents an asynchronous operation, while' Task<T>' represents an asynchronous operation that returns a result of type 'T'.

3. Returning Task and Task<T>: Async methods return either 'Task' or 'Task<T>'. If the method returns 'void', it can be made asynchronous by returning 'Task'. If it returns a result, you can make it asynchronous by returning 'Task<T>'.

4. Error Handling: Error handling in asynchronous methods can be done using try-catch blocks inside the method, just like synchronous methods. Additionally, you can handle errors from awaited tasks using try-catch blocks around 'await' statements.

5. Async in LINQ Queries: Starting from C# 7.0, you can use 'async' and 'await' in LINQ queries, allowing you to perform asynchronous operations within LINQ queries.

• Programing example:

using System;
using System.Threading.Tasks;

class Program
{
    static async Task＜int> FetchDataAsync()
    {
        // Simulating asynchronous operation
        await Task.Delay(1000); // Wait for 1 second
        return 42;
    }

    static async Task Main()
    {
        Console.WriteLine("Fetching data...");
        int result = await FetchDataAsync();
        Console.WriteLine($"Data fetched: {result}");
    }
}

Fetching data...
Data fetched: 42

Key Takeaways:

• Async and await in C# simplify asynchronous programming by allowing you to write code that looks synchronous but behaves asynchronously.

• Asynchronous programming improves the responsiveness of applications, especially in scenarios where waiting for I/O operations.

• Proper error handling is crucial in asynchronous methods to handle exceptions effectively.

Note: Async and await are powerful features in C# that enable developers to write more responsive and scalable applications, especially in scenarios involving I/O-bound operations.

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

class Program
{
    static async Task＜string> FetchDataAsync()
    {
        string url = "https://www.techbaz.org/about.txt";
        
        using HttpClient client = new();
            HttpResponseMessage response = await client.GetAsync(url);
            if (response.IsSuccessStatusCode)
            {
                return await response.Content.ReadAsStringAsync();
            }
            else
            {
                throw new Exception($"Fetch Failed {url}. Code: {response.StatusCode}");
            }
    }

    static async Task Main()
    {
        Console.WriteLine("Fetching data...");
        string result = await FetchDataAsync();
        Console.WriteLine($"Data fetched: {result}");
    }
}

Data fetched: -> 'Techbaz' is a project of free IT education.