C# Thread Class

In the C# programming language, a thread is the smallest unit of execution in a program. It represents a separate path of execution. It allows multiple tasks to run at the same time. It helps to improve performance by making better use of the CPU. Every C# program begins with a main thread, which is automatically created by the .NET runtime. We can also create extra threads to run other tasks at the same time as the main method.

In C#, the Thread class is defined in the System.Threading namespace. It is commonly used to create and manage threads.

Syntax:

It has the following syntax.

Thread t = new Thread (new ThreadStart(MethodName));

t.Start();

When we are using a lambda expression.

Thread t = new Thread(() => {

    // thread code here

});

t.Start();

In this syntax,

• ✅ ThreadStart: It is a delegate that points to a method that will run inside the new thread.
• ✅ MethodName: It defines the name of the method that we want to execute.

C# Thread Class Example

Let us take an example to illustrate the thread class in C#.

Example

using System;

using System.Threading;

class C# Tutorial

{

    static void Num()

    {

        for (int m = 1; m <= 3; m++)

        {

            Console.WriteLine("Thread " + Thread.CurrentThread.Name + ": " + m);

            Thread.Sleep(500); // Pause for 0.5 seconds

        }

    }

    static void Main()

    {

        Thread m1 = new Thread(Num);

        m1.Name = "Worker";

        m1.Start();    // Start the thread

        m1.Join();     // Wait until m1 finishes

        Console.WriteLine("Thread finished. Main thread exiting.");

    }

}

Output:

Thread Worker: 1

Thread Worker: 2

Thread Worker: 3

Thread finished. Main thread exiting.

Explanation:

In this example, we have created a thread to execute a method named Num. The Num method prints the numbers from 1 to 3, which takes a short pause after each iteration. In the main function, we create an instance m1 and call the Start method, and then call m1.Join method ensures the main thread waits until the worker thread completes its execution before printing the final message.

Key Features of the C# Thread Class

There are several features of the Thread class in C#. Some main features are as follows:

• ✅ It is defined in the System.Threading namespace.
• ✅ It defines a single thread of execution.
• ✅ A thread may be created using a delegate. It can be either with a method reference or a lambda expression.
• ✅ A thread in C# supports foreground and background modes.
• ✅ It offers several properties, including Priority, Name, IsAlive, and methods like Abort, Start, Sleep, and Join.

Properties and Methods of the Thread Class

Here is a list of the most commonly utilized properties of the thread class in C#. These are as follows:

C# Thread Class Property Example

Let us take an example to illustrate the properties of threads in C#.

Example

using System;

using System.Threading;

class C# Tutorial

{	

    static void TechTask()

    {

        for (int i = 1; i <= 3; i++)

        {

            Console.WriteLine("Executing Thread " + Thread.CurrentThread.Name + ": Step " + i);

            Thread.Sleep(500);

        }

    }

    static void Main()

    {

        Thread m1 = new Thread(TechTask);

        m1.Name = "WorkerThread";

        m1.Priority = ThreadPriority.Highest; 

        m1.IsBackground = true;  

        Console.WriteLine("Thread Details - Name: " + m1.Name + 

                          ", Priority: " + m1.Priority + 

                          ", Background: " + m1.IsBackground);

        m1.Start();

        m1.Join();

        Console.WriteLine("Is the thread still running? " + m1.IsAlive);

    }

}

Output:

Thread Details - Name: WorkerThread, Priority: Highest, Background: True

Executing Thread WorkerThread: Step 1

Executing Thread WorkerThread: Step 2

Executing Thread WorkerThread: Step 3

Is the thread still running? False

Explanation:

In this example, we demonstrate how to create and manage a thread using the C# Thread class. First, we create a worker thread (m1) to run the TechTask method, which gives a name, the highest priority, and sets it as a background thread. After that, the Start method starts execution, and then calls the Join function that makes the main thread wait until the worker thread finishes. Finally, the IsAlive checks whether the thread is still running.

Thread Class Methods

The following table shows the methods of the Thread class in C#.

C# Thread Methods Example using Thread Start, Sleep, and Join

Let us take an example to illustrate the Thread Start, Sleep, and Join methods in C#.

Example

using System;

using System.Threading;

class C# Tutorial

{

    static void Number()

    {

        for (int m = 1; m <= 5; m++)

        {

            Console.WriteLine("Thread: Printing number " + m);

            Thread.Sleep(500); 

        }

    }

    static void Main()

    {

        // Create an instance of thread

        Thread m1 = new Thread(Number);

        Console.WriteLine("Main thread starting m1...");

        m1.Start(); // Start the thread

        // Wait for m1 to finish

        m1.Join();

        Console.WriteLine("m1 has completed \nThe main threads ends here.");

    }

}

Output:

Main thread starting m1...

Thread: Printing number 1

Thread: Printing number 2

Thread: Printing number 3

Thread: Printing number 4

Thread: Printing number 5

m1 has completed 

The main threads ends here.

Explanation:

In this example, we have created a thread to run the Number method, which prints numbers from 1 to 5 with a short delay. In the main function, we create an instance m1 and call the Start method, and then call m1.Join method ensures the main thread waits until the worker thread completes its execution before printing the final message.

Thread Class Constructor in C#

In C#, the Thread class constructor provides four constructors as follows.

1) Thread(ThreadStart start)

It is the constructor of the Thread class in C#. It initializes a new thread that will execute a method. It is specified by a ThreadStart delegate that signifies the methods to be invoked on the new thread.

2) Thread(ParameterizedThreadStart start)

The Thread(ParameterizedThreadStart start) in C# initializes a new instance of the Thread class. It specifies a delegate that enables an object to be passed to the thread when it starts execution.

start: It is a delegate that shows the method to be executed when the thread starts executing. If the start parameter is null, it throws an ArgumentNullException.

3) Thread(ThreadStart start, int maxStackSize)

In C#, the Thread(ThreadStart start, int maxStackSize) initializes a new instance of the Thread class. It defines the maximum stack size for the thread.

start: It is a ThreadStart delegate that shows the methods to be executed when the thread starts.

maxStackSize: It defines the maximum stack size for the thread. We have to use 0 to apply the default maximum stack size defined in the header for the executable.

4) Thread(ParameterizedThreadStart start, int maxStackSize)

This constructor initializes the thread class. It allows us to delegate, which enables an object to be passed to the thread using a ParameterizedThreadStart delegate. It defines the maximum stack size for the thread.

Advantages of the Thread Class in C#

There are several advantages of the thread class in C#. Some of them are as follows:

• ✅ It is used to keep UI responsive for applications while background tasks are running.
• ✅ It has better CPU utilization while developing applications.
• ✅ It enables parallel execution that helps to perform multiple tasks at the same time.
• ✅ It helps to improve the application performance.

Disadvantages of the Thread Class in C#

There are several disadvantages of the Thread Class in C#. Some main disadvantages are as follows:

• ✅ It is very complex to handle.
• ✅ It has some synchronization issues, such as race conditions and deadlocks.
• ✅ It uses higher memory that contains several threads.

Conclusion

In conclusion, the C# Thread class is an essential class to run multiple tasks at the same time. It enables us to create, start, pause, resume, and stop threads. It helps to improve performance by making better use of the CPU. It has several property and methods that handles multiple operations.

C# Thread Class FAQs

1) What is a thread class in C#?

In C#, a thread is the smallest unit of execution in a program. It represents a separate path of execution. It enables multiple operations to run at the same time. It helps to improve performance by making better use of the CPU.

2) How do we create a thread in C#?

We can create a thread using the thread constructor and pass the method.

Thread t = new Thread(new ThreadStart(MethodName));

t.Start();

3) Can we restart a thread once it has finished execution?

No, once a thread has completed its execution, it cannot be restarted. If we need to run the code again, we must create a new Thread object.

4) What is the Thread.Abort method?

The Thread.Abort method is commonly utilized to terminate a running thread by throwing a ThreadAbortException.

5) What is the main difference between Thread.Sleep and Task.Delay?

Thread.Sleep(milliseconds): It pauses the current thread. It has been blocked for the specified time.

Task.Delay(milliseconds): It creates an asynchronous delay without blocking the thread. It allows other tasks to run concurrently.