Foreground and background does not affect to each other.

Example:

To creating Foreground and Background thread writes the following code.

using System.Threading;
  
namespace ForegroundThread
{
     class Program
    {
         static voidMain(string[] args)
         {
             // Create ThreadA object
             Thread back= newThread(newThreadStart(ChildThreadA));
             // Create ThreadB object
             Thread fore= newThread(newThreadStart(ChildThreadB));
             // Set ThreadB as background thread
            back.IsBackground= true;
            back.Start();
            fore.Start();
             
             Thread.CurrentThread.Name= "Main";
            for (inti=0; i<20; i++)
            {
                 if (i==5)
                     fore.Abort();  //Abort Foreground thread
                Console.WriteLine(Thread.CurrentThread.Name);
            }
  
       }
         public staticvoidChildThreadA()
         {
             for (inti=0; i<10; i++)
            {
                 Console.WriteLine("Child thread A:");
            }
         }
         public staticvoidChildThreadB()
         {
             for (inti=0; i<10; i++)
            {
                 Console.WriteLine("Child thread B:");
            }
         }
    }
}

In above program after terminating of foreground thread the application will run until main thread is not terminated after terminating main thread application will be terminate.

Output: