Single instance of application in C#

There is some application that we want that only single instance of application works at a time. So here is the logic for doing that:

Here I am getting process list and I check whether the there is process with same name of current process. If yes then processlist.length will be greater than one, then we exit from the new instance.

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.Diagnostics;

namespace Single_Instance

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            checkinstance();

            // now you can do your application proceduren

        }

        public void checkinstance()

        {

            Process[] thisnameprocesslist;

            string modulename, processname;

            Process p = Process.GetCurrentProcess();

            modulename = p.MainModule.ModuleName.ToString();

            processname = System.IO.Path.GetFileNameWithoutExtension(modulename);

            thisnameprocesslist = Process.GetProcessesByName(processname);

             if (thisnameprocesslist.Length > 1)

            {

                MessageBox.Show("Instance of this application is already running.");

                Application.Exit();

            }

        }

    }

}