聽說讀寫

using System;
using System.Threading;
public static class Program
{
    public static void Main()
    {
        Boolean createdNew;
        // Try to create a kernel object with the specified name
        using (new Semaphore(0, 1, "SomeUniqueStringIdentifyingMyApp", out createdNew))
        {
            if (createdNew)
            {
                // This thread created the kernel object so no other instance of this
                // application must be running. Run the rest of the application here...
            }
            else
            {
                // This thread opened an existing kernel object with the same string name;
                // another instance of this application must be running now.
                // There is nothing to do in here, let's just return from Main to terminate
                // this second instance of the application.
            }
        }
    }
}