WPF开发中遇到的新知识 -- 1

前后台同时启动的方式

目的：希望在WPF前台启动后，带动 ASP.NET Core 后台服务一同启动，在前台关闭后，也一起关闭

方法：在打开窗口之前，首先手动打开 ASP.NET Core 子进程，然后注册窗口关闭回调，通知后台关闭进程

public static class ExternalProcessFactory
    {

        private static Process Process;

        public static Process GetApp()
        {
            if (Process != null)
            {
                return Process;
            }

            Process process = new Process();
            //var app = Environment.CurrentDirectory + "/xxx.exe";
            var app = "D:\\xxx.exe";
            process.StartInfo.FileName = app;
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.RedirectStandardOutput = false;
            process.StartInfo.RedirectStandardError = false;
            process.StartInfo.RedirectStandardInput = false;
            process.StartInfo.CreateNoWindow = false;
            //process.StartInfo.WorkingDirectory = Environment.CurrentDirectory;
            process.StartInfo.WorkingDirectory = "D:\\workspace";
            Process = process;
            return process;
        }

        public static void Close(int? timeoutMilliseconds = null)
        {
            if (Process == null || Process.HasExited)
            {
                return;
            }

            if (AttachConsole((uint)Process.Id))
            {
                SetConsoleCtrlHandler(null, true);

                GenerateConsoleCtrlEvent(CtrlTypes.CTRL_C_EVENT, 0);

                FreeConsole();

                if (timeoutMilliseconds != null)
                {
                    Process.WaitForExit(timeoutMilliseconds.Value);
                }
                else
                {
                    Process.WaitForExit();
                }

                SetConsoleCtrlHandler(null, false);
            }
        }

        [DllImport("kernel32.dll")]
        private static extern bool AttachConsole(uint dwProcessId);

        [DllImport("kernel32.dll")]
        private static extern bool FreeConsole();

        [DllImport("kernel32.dll")]
        private static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate? HandlerRoutine, bool Add);

        [DllImport("kernel32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool GenerateConsoleCtrlEvent(CtrlTypes dwCtrlEvent, uint dwProcessGroupId);

        enum CtrlTypes : uint
        {
            CTRL_C_EVENT = 0,
            CTRL_BREAK_EVENT,
            CTRL_CLOSE_EVENT,
            CTRL_LOGOFF_EVENT = 5,
            CTRL_SHUTDOWN_EVENT
        }

        private delegate bool ConsoleCtrlDelegate(CtrlTypes ctrlTypes);
    }

大部分代码都是查询了如何发送 CTRL_C 信号给控制台应用，使得可以优雅关闭的代码，剩下的只需要编写创建子进程的部分，我们需要填充一些子进程的基本信息

• CreateNoWindow，如果不需要子进程打开窗口，而是后台运行，可以设置为 true
• WorkingDirectory，这个比较重要，如果不设置启动的环境，可能会出现配置文件读取不成功的问题
• FileName，我是直接将两个项目发布到同一个文件夹下，所以只需要 Environment.CurrentDirectory 就可以找到了