只允许运行一个客户端实例

Posted 2022-12-05 Jia_ShengJie

 internal static class Program
    
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        private static void Main()
        
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            SysHelper.RunFrmOnly<FrmMain>();
        
    

    public static class SysHelper
    
        /// <summary>
        /// 唯一运行一个实例,第二次打开时会把首次运行的置顶
        /// 缺陷：(1)应用程序改名后无效  (2)如果首次运行的界面最大化，置顶时，界面会缩小，需要手动调整
        /// </summary>
        /// <typeparam name="T">运行的窗体</typeparam>
        public static void RunFrmOnly<T>() where T : new()
        
            Process instance = RunningInstance();
            if (instance == null)
            
                Form frm = new T() as Form;
                Application.Run(frm);
            
            else
            
                HandleRunningInstance(instance);
            
        

        [DllImport("User32.dll")]
        private static extern bool SetForegroundWindow(IntPtr hWnd);

        [DllImport("User32.dll")]
        private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);

        private static void HandleRunningInstance(Process instance)
        
            // 确保窗口没有被最小化或最大化
            ShowWindowAsync(instance.MainWindowHandle, 4);
            // 设置真实例程为foreground  window
            SetForegroundWindow(instance.MainWindowHandle); // 放到最前端
        

        private static Process RunningInstance()
        
            Process current = Process.GetCurrentProcess();
            Process[] processes = Process.GetProcessesByName(current.ProcessName);
            return processes.Where(process => process.Id != current.Id).FirstOrDefault(
                process => Assembly.GetExecutingAssembly().Location.Replace("/", "\\\\") == current.MainModule.FileName);