App.xaml.cs

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

namespace EdGo
{
    /// <summary>
    /// Логика взаимодействия для App.xaml
    /// </summary>
    /// 
    	

    public partial class App : Application
    {
        private static Mutex mutex = new Mutex(true, "1f2886dd-1217-4b97-9709-21c6c04597d1");
        private static MainWindow mainWindow = null;

        public App()
        {
            InitializeComponent();
        }

        [STAThread]
        static void Main()
        {
            if (mutex.WaitOne(TimeSpan.Zero, true))
            {
                App app = new App();
                mainWindow = new MainWindow();
                mainWindow.Show();
                app.Run(mainWindow);
                mutex.ReleaseMutex();
            }
            else
            {
                BringWindowToFront();
            }
        }

        [DllImport("user32.dll")]
        public static extern IntPtr FindWindow(string className, string windowTitle);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool ShowWindow(IntPtr hWnd, ShowWindowEnum flags);

        [DllImport("user32.dll")]
        private static extern int SetForegroundWindow(IntPtr hwnd);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool GetWindowPlacement(IntPtr hWnd, ref Windowplacement lpwndpl);

        private enum ShowWindowEnum
        {
            Hide = 0,
            ShowNormal = 1, ShowMinimized = 2, ShowMaximized = 3,
            Maximize = 3, ShowNormalNoActivate = 4, Show = 5,
            Minimize = 6, ShowMinNoActivate = 7, ShowNoActivate = 8,
            Restore = 9, ShowDefault = 10, ForceMinimized = 11
        };

        private struct Windowplacement
        {
            public int length;
            public int flags;
            public int showCmd;
            public System.Drawing.Point ptMinPosition;
            public System.Drawing.Point ptMaxPosition;
            public System.Drawing.Rectangle rcNormalPosition;
        }

        static void BringWindowToFront()
        {
            IntPtr wdwIntPtr = FindWindow(null, "ED-GO Event Client");

            //get the hWnd of the process
            Windowplacement placement = new Windowplacement();
            GetWindowPlacement(wdwIntPtr, ref placement);

            // Check if window is minimized
            if (placement.showCmd == 2)
            {
                //the window is hidden so we restore it
                ShowWindow(wdwIntPtr, ShowWindowEnum.Restore);
            }
        }

        }
    }