using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Reflection;
using System.Text;

namespace Server_Download
{
    static class Program
    {
        /// 该函数设置由不同线程产生的窗口的显示状态  
        /// </summary>  
        /// <param name="hWnd">窗口句柄</param>  
        /// <param name="cmdShow">指定窗口如何显示。查看允许值列表，请查阅ShowWlndow函数的说明部分</param>  
        /// <returns>如果函数原来可见，返回值为非零；如果函数原来被隐藏，返回值为零</returns>  
        //[DllImport("User32.dll")]
       // private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);

        /// <summary>  
        ///  该函数将创建指定窗口的线程设置到前台，并且激活该窗口。键盘输入转向该窗口，并为用户改各种可视的记号。  
        ///  系统给创建前台窗口的线程分配的权限稍高于其他线程。   
        /// </summary>  
        /// <param name="hWnd">将被激活并被调入前台的窗口句柄</param>  
        /// <returns>如果窗口设入了前台，返回值为非零；如果窗口未被设入前台，返回值为零</returns>  
        [DllImport("User32.dll")]
        private static extern bool SetForegroundWindow(IntPtr hWnd);
        private const int SW_SHOWNOMAL = 1;

        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        
       
        static void Main()
        {
            Process process = RunningInstance();
            if (process != null)
            {
                //MessageBox.Show("应用程序已经在运行中。。。");
                HandleRunningInstance(process);
                //System.Threading.Thread.Sleep(1000);  
                System.Environment.Exit(1);
            }

            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());



        }
        [DllImport("user32.dll")]
        private static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
        [DllImport("user32.dll", EntryPoint = "ShowWindowAsync")]
        public static extern bool ShowWindowAsync(IntPtr hWnd, bool nCmdShow);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);




        private static void HandleRunningInstance(Process instance)
        {
            Form1 form1 = new Form1();
            IntPtr hwnd = FindWindow(null, form1.Text);//"Download"
            ShowWindow(hwnd, 1);
            SetForegroundWindow(hwnd); //当到最前端  

        }
        public static Process RunningInstance()
        {
            Process currentProcess = Process.GetCurrentProcess();
            Process[] Processes = Process.GetProcessesByName(currentProcess.ProcessName);
            foreach (Process process in Processes)
            {
                if (process.Id != currentProcess.Id)
                {
                    if (Assembly.GetExecutingAssembly().Location.Replace("/", "\\") == currentProcess.MainModule.FileName)
                    {
                        return process;
                    }
                }
            }
            return null;
            throw new NotImplementedException();
        }



    }
}
