只運行一個程式之一

using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Diagnostics;
using System.Reflection;

namespace WindowsApplication1
...{
    static class Program
    ...{
        /**//// <summary>
        /// 應用程式的主要進入點。
        /// </summary>
        [STAThread]
        static void Main()
        ...{
            Process p = checkApp();
            if (p == null)
            ...{
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Form1());
            }
            else
            ...{
                MessageBox.Show("該程式正在執行","友情提醒",MessageBoxButtons.OK,MessageBoxIcon.Information);
            }
        }

        private static Process checkApp()
        ...{
            //獲取當前進程
            Process current = Process.GetCurrentProcess();
            //通過進程名稱查找進程
            Process[] processes = Process.GetProcessesByName(current.ProcessName);
            foreach (Process process in processes)
            ...{
                if (process.Id != current.Id)
                ...{
                    //確保例程從EXE文件執行
                    if (Assembly.GetExecutingAssembly().Location.Replace("/", "\") == current.MainModule.FileName)
                    ...{
                        //返回另一個例程實例
                        return process;
                    }
                }
            }
            return null;
        }
    }
}