As software developers, we often come across situations where certain tasks must be executed sequentially. However, there are also moments where we need to have several processes running simultaneously.
This is where the concepts of synchronous and asynchronous programming come in. Synchronous programming in C# involves executing tasks sequentially.
In other words, a program waits for a particular action to complete before moving on to the next one. This approach can be beneficial for certain use cases, such as blocking architectures that require a certain order of events.
However, synchronous programming is not always the most efficient approach, particularly in reactive programming systems where user input must be responded to in real-time.
On the other hand, asynchronous programming comes to fancy for its ability to create applications that can perform several tasks simultaneously.
Asynchronous programs are multithreaded, enabling non-blocking execution of multiple tasks. This approach is especially useful for networking and communications since multiple requests are often sent simultaneously, and waiting for a response can be time-consuming.
Asynchronous programming can improve application performance by executing multiple threads simultaneously, thus enabling more efficient use of system resources. To implement asynchronous programming in C#, one must use the async and await keywords.
These keywords enable the execution of asynchronous code on the stack, with awaitable methods being able to pause the code execution and return focus to the caller of the method. The Task is a common base class for asynchronous programming in .NET, and it represents a unit of work that can be scheduled to execute on a thread pool thread.
Implementing asynchronous programming involves using the Task-based Asynchronous Pattern(TAP) that enhances scalability and responsiveness. The TAP model is beneficial in multiple ways.
First, the return type task object allows you to perform additional operations while waiting for the main task to complete. Second, it keeps the current thread free, while waiting for the completion of the task, leading to improved scalability and responsiveness.
By using the async and await keywords with the TAP pattern, you can write asynchronous code more efficiently. When implementing async methods in C#, it is essential to await all the individual tasks in a method before returning, especially when needing responses from multiple sources.
In this case, you can use the WhenAll method. WhenAll is provided as an extension method of the Task class, and it waits asynchronously for all the tasks to be completed.
The method returns an array of results for all the completed tasks in the order in which the tasks were provided. In summary, asynchronous programming in C# is a widely used programming paradigm capable of improving system performance, scalability and responsiveness by executing multiple tasks simultaneously.
The async and await keywords, especially when used with the TAP pattern and the WhenAll method, helps developers write efficient asynchronous code. Keep in mind that synchronous programming, while it has its place, is unlikely to offer as significant performance improvements as asynchronous programming in modern application development.
Code examples are an excellent way to clarify the concepts learned. In this section, we will provide you with sample codes that illustrate how to apply synchronous programming, asynchronous programming, and multiple awaiting tasks in C#.
Synchronous Programming Example
Consider the following code snippet that demonstrates synchronous programming in C#:
“`
static void Main(string[] args)
{
Console.WriteLine(“Process1 starts.”);
Process1();
Console.WriteLine(“Process2 starts.”);
Process2();
Console.WriteLine(“All Processes Finished.”);
}
static void Process1()
{
Thread.Sleep(3000);
Console.WriteLine(“Process1 finished.”);
}
static void Process2()
{
Thread.Sleep(2000);
Console.WriteLine(“Process2 finished.”);
}
“`
In this example, two methods, Process1 and Process2, are defined. These methods contain some blocking code (represented by the Thread.Sleep() method) that will delay the code execution for several seconds.
The Main() method then calls these two methods synchronously. The result is that the console output will show each process being executed sequentially with a delay of about 5 seconds.
Asynchronous Programming Example
Now, let’s consider the asynchronous programming example where the same set of methods are applied:
“`
static async Task Main(string[] args)
{
Console.WriteLine(“Process1 starts.”);
await Process1Async();
Console.WriteLine(“Process2 starts.”);
await Process2Async();
Console.WriteLine(“All Processes Finished.”);
}
static async Task Process1Async()
{
await Task.Delay(3000);
Console.WriteLine(“Process1 finished.”);
}
static async Task Process2Async()
{
await Task.Delay(2000);
Console.WriteLine(“Process2 finished.”);
}
“`
Here, we make use of the async and await keywords along with the Task.Delay() method, which pauses the execution for a specific duration without blocking the thread. The keyword async allows these methods to be executed asynchronously, with the await keyword instructing the program to pause and wait for the task to complete before continuing execution.
The async and await keywords create a list of tasks that get executed concurrently when used with multithreading. Here, the program will execute the two tasks concurrently, reducing the overall execution time significantly.
Multiple Awaiting Tasks Example
Consider this modified version of the previous asynchronous example that makes multiple awaiting tasks:
“`
static async Task DoSomeTask()
{
Console.WriteLine(“Process1 starts.”);
Task process1=Process1Async();
Console.WriteLine(“Process2 starts.”);
Task process2=Process2Async();
await Task.WhenAll(process1,process2);
Console.WriteLine(“All Processes Finished.”);
}
“`
Here, the DoSomeTask() method creates two tasks, process1 and process2. We then use the WhenAll() method to wait for all the tasks to be completed, before printing the “All Processes Finished” message.
In summary, the above replicas demonstrate how we can use synchronous programming, asynchronous programming, and multiple awaiting tasks in C#. The synchronous approach is useful in instances where the execution order needs to be sequential, while the asynchronous approach is superior where multiple processes can be executed simultaneously.
Finally, multiple awaiting tasks are particularly handy when theres a need to execute simultaneous asynchronous processes. In summary, this article highlights the importance of understanding synchronous and asynchronous programming in C#, and how they can be implemented in various contexts.
Synchronous programming is useful for sequential execution, while asynchronous programming is useful for executing multiple processes simultaneously, and multiple awaiting tasks are beneficial in executing asynchronous processes with dependencies. Utilizing the async and await keywords in combination with the TAP model can lead to more efficient and scalable applications.
As a software developer, it is crucial to know when to use each approach and how they can improve application performance, scalability, and responsiveness. Remember to choose the best approach based on the specific project conditions and requirements to make the most of the programming languages’ capabilities.