How to check whether a thread is alive or not in C#

A Thread class is responsible for creating and managing a thread in multi-thread programming. It provides a property known as IsAlive to check if the thread is alive or not. Or in other words, the value of this property indicates the current execution of the thread.

Syntax:

public bool IsAlive { get; }

Return Value: This property returns true if the thread is started and not terminated normally or aborted. Otherwise, return false. The return type of this property is System.Boolean.

Below programs illustrate the use of IsAlive property:

Example 1:

// C# program to illustrate the
// use of IsAlive property
using System;
using System.Threading;

public class GFG {

    // Main Method
    static public void Main()
    {
        Thread thr;

        // Get the reference of main Thread
        // Using CurrentThread property
        thr = Thread.CurrentThread;

        // Display the current state of
        // the main thread Using IsAlive
        // property
        Console.WriteLine("Is main thread is alive"+
                            " ? : {0}", thr.IsAlive);
    }
}

Output:

Is main thread is alive ? : True

Example 2:

// C# program to illustrate the
// use of IsAlive property
using System;
using System.Threading;

public class GFG {

    // Main method
    public static void Main()
    {
        // Creating and initializing threads
        Thread Thr1 = new Thread(new ThreadStart(job));
        Thread Thr2 = new Thread(new ThreadStart(job));

        // Display the current state of
        // the threads Using IsAlive
        // property
        Console.WriteLine("Is thread 1 is alive : {0}",
                                         Thr1.IsAlive);

        Console.WriteLine("Is thread 2 is alive : {0}",
                                         Thr2.IsAlive);
        Thr1.Start();
        Thr2.Start();

        // Display the current state of
        // the threads Using IsAlive
        // property
        Console.WriteLine("Is thread 1 is alive : {0}",
                                         Thr1.IsAlive);

        Console.WriteLine("Is thread 2 is alive : {0}",
                                         Thr2.IsAlive);
    }

    // Static method
    public static void job()
    {
        Thread.Sleep(2000);
    }
}

Output:

Is thread 1 is alive : False
Is thread 2 is alive : False
Is thread 1 is alive : True
Is thread 2 is alive : True

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.threading.thread.isalive?view=netframework-4.7.2