Tasks in C#

Tasks in C# is nothing but an operation or a work that executes in asynchronous manner. It was introduced in .Net framework 4.0 to support asynchronous functionality, in-fact the Task Parallel Library which is known as TPL is based on the concept of Tasks.

C#.NET

Tasks in C#
Tasks in C# is nothing but an operation or a work that executes in asynchronous manner. It was introduced in .Net framework 4.0 to support asynchronous functionality, in-fact the Task Parallel Library which is known as TPL is based on the concept of Tasks.

What is a Task in C# ?

In C# Task is basically used to implement asynchronous programming model, the .Net runtime executes a Task object asynchronously on a separate thread from the thread pool.

The Task Scheduler in .Net framework is responsible to execute the Task , by default it requests a worker thread from the Thread Pool to execute the Task . Here, the thread pool determines, whether to create a new thread or reuse an existing thread from the thread pool to execute the operation.

Creating Tasks in C# ?

To create a Task in C#, first you need to import System.Threading.Tasks namespace in to your program, then you can use the Task class to create object and access its properties.

//Create a task instance 
 Task t = new Task(PrintEvenNumbers);
//Start the task 
t.Start();
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Example – 1 : Creating Tasks in C# using Task class and Start method

In below example, we have created a Task object as Task t , passing the method PrintEvenNumbers; in the constructor, then we invoke the Task t by t.Start(); method.

using System;
using System.Threading.Tasks;
namespace TaskInCshap
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a task instance
            Task t = new Task(PrintEvenNumbers);
            //Start the task
            t.Start();
            Console.Read();
        }
        public static void PrintEvenNumbers()
        {
            Console.WriteLine("Even numbers less than 10");
            for (int i = 0; i <= 10; i++)
                if(i%2 == 0)
                    Console.WriteLine("Number : {0}", i);        
        }
    }
}
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When we run above example, it generates below output, here the task executes in a separate thread and prints the even numbers on the console window.

Different ways of creating Tasks in C#:

There are various ways available in C#.Net 4.0 to create a Task object. Please find some of the different ways as follows.

Task Creation using Factory method :

We can also use Task.Factory() method to creates a task instance and invoke it in a single line of code, as follows.

//Create a task and invoke it
Task.Factory.StartNew(PrintEvenNumbers);
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Task creation using Action Generic Delegate :

You can use below syntax to create a task using Action type (Generic Delegate) , In below code example, we have created a task object and then invoking it.

//Create a Task using Action delegate
Task t = new Task(new Action(PrintEvenNumbers));
//Invoke Task
t.Start();
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Task creation using a Delegate :

In below code sample, we are using delegate keyword to create a task instance and then invoking it.

//Create a Task using delegate
Task t = new Task(delegate { PrintEvenNumbers(); });
//Invoke Task
t.Start();
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Task creation using Action Generic Delegate :

You can use below syntax to create a task using Action type (Generic Delegate) , In below code example, we have created a task object and then invoking it.

//Create a Task using Action delegate
Task t = new Task(new Action(PrintEvenNumbers));
//Invoke Task
t.Start();
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Task creation using a Delegate :

In below code sample, we are using delegate keyword to create a task instance and then invoking it.

//Create a Task using delegate
Task t = new Task(delegate { PrintEvenNumbers(); });
//Invoke Task
t.Start();
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Similarly, we can also use Task.Run() method to create a task object and invoke it in single line, as follows.

//Invoke it directly using Run method
Task t = Task.Run(delegate { PrintEvenNumbers(); });
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Task creation using Lambda and named method :

In below code sample, we are using lambda and named method expression to create a task instance and then invoking it.

//Creating a Task instance using lambda and named method 
Task t = new Task(() => PrintEvenNumbers());
//Invoke Task
t.Start();
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Similarly we can also use Task.Run() method to create a task object and invoke it in single line, as follows.

//Invoke it directly using Run method
Task t = Task.Run(() => PrintEvenNumbers());
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