C# 激活正在运行的程序

static class Program
    {
        //给这个程序主窗体起个名字
        private static string strProcessName = "Form1";
        private static string strAppName = "WindowsFormsApplication1";
        static int hWnd = 0;
        //随便个数字，用来做判断
        const int SW_SHOW = 1;
        //指定是那个DLL，或者进程
        [DllImport("user32.dll", EntryPoint = "ShowWindow")]
        public static extern int ShowWindow(int hwnd, int nCmdShow);

        [DllImport("user32")]
        public static extern int GetWindowText(int hWnd, StringBuilder lpString, int nMaxCount);

        [DllImport("user32")]
        public static extern int EnumWindows(CallBack x, int y);

        public delegate bool CallBack(int hWnd, int lParam);

        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            //进程数组
            Process[] ps = Process.GetProcessesByName(strAppName);
            //声明个委托
            CallBack myCallBack = new CallBack(FineAppWindow);
            EnumWindows(myCallBack, 0);
            
            if (ps.Length > 1)
            {//如果进程里面有这个
                ShowWindow(hWnd, SW_SHOW);
                return;
            }
            else
            {
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Form1());
            }
        }

        public static bool FineAppWindow(int hwnd, int lParam)
        {
            StringBuilder sb = new StringBuilder(200);
            int n = GetWindowText(hwnd, sb, 200);

            if (sb.ToString() == strProcessName)
            {
                hWnd = hwnd;
            }
            return true;
        }
    }

调用的是系统的一个类库，代码也是在网上找到 就直接贴上去了 收藏，希望作者见了勿怪！非原创