Multi Threading and threadpriority problems

Reason for the error is before starting your thread you need to set a priority for each thread.

 With the setPriority method, you can increase or decrease the priority of any thread

namespace Threads  
{  
    public partial class FrmbasicThread : Form  
    {  
        public FrmbasicThread()  
        {  
            InitializeComponent();  
        }  
        private Thread ThreadA, ThreadB, ThreadC, ThreadD;  
  
        private void button1_Click(object sender, EventArgs e)  
        {  
  
            Console.WriteLine("------------------");  
            Console.WriteLine(string.Format("-Before Starting Thread-"));  
            ThreadStart aa = new ThreadStart(Name1);  
  
            ThreadA = new Thread(aa);  
            ThreadA.Name = "Thread A Process";  
  
            ThreadB = new Thread(new ThreadStart(Name2));  
            ThreadB.Name = "Thread B Process";  
  
            ThreadC = new Thread(new ThreadStart(Name3));  
            ThreadC.Name = "Thread C Process";  
  
            ThreadD = new Thread(new ThreadStart(Name4));  
            ThreadD.Name = "Thread D Process";  
  
            ThreadA.Priority = ThreadPriority.Highest;  
            ThreadB.Priority = ThreadPriority.Normal;  
            ThreadC.Priority = ThreadPriority.AboveNormal;  
            ThreadD.Priority = ThreadPriority.BelowNormal;   
  
            ThreadA.Start();  
            ThreadB.Start();  
            ThreadC.Start();  
            ThreadD.Start();  
  
            ThreadA.Join();  
            ThreadB.Join();  
            ThreadC.Join();  
            ThreadD.Join();  
        
  
            Console.WriteLine(string.Format("-After Starting Thread-"));  
  
            lblResult.Text = "-After Starting Thread-";  
        }  
        static void Name1()  
        {  
  
            for (int i = 0; i <= 2; i++)  
            {  
                Console.WriteLine("Name of Thread " + Thread.CurrentThread.Name+ " = " + i);  
                Thread.Sleep(500);  
            }  
        }  
        static void Name3()  
        {  
            for (int i = 0; i <= 6; i++)  
            {  
                Console.WriteLine("Name of Thread " + Thread.CurrentThread.Name + " = " + i);  
                Thread.Sleep(500);  
            }  
        }  
        static void Name2()  
        {  
            for (int i = 0; i <= 2; i++)  
            {  
                Console.WriteLine("Name of Thread " + Thread.CurrentThread.Name + " = " + i);  
                Thread.Sleep(500);  
            }  
        }  
        static void Name4()  
        {  
            for (int i = 0; i <= 6; i++)  
            {  
                Console.WriteLine("Name of Thread " + Thread.CurrentThread.Name + " = " + i);  
                Thread.Sleep(1500);  
            }  
        }  
        private void label1_Click(object sender, EventArgs e)  
        {  
  
        }  
    }  
}