A developer's blog

I run a simple web server to serve as a storage medium for my mobile devices (I don’t like using dropbox or other online storage solutions because they don’t offer much space and they hogs up bandwidth unnecessarily). Before I go to sleep I usually shut down the server to save energy, but in order to do so, I have to have another computer turned on to perform remote access into the server and shut it down via command line. Occasionally, I would turn off my work computer before I remember that I want to shut down the server and I’m too lazy by then to turn on my work computer again.

That’s why I wanted an application that is capable of shutting down Windows on my behalf. The scenario is like this: because I can access FTP service from my phone, I will create a file, namely ‘shutdown’; when the server sees this file, it will delete the file and initiate shutdown. Quite simple.

To shut down, I use Windows management interface (System.Management namespace in C#)

        static void Shutdown()
        {
            ManagementBaseObject mboShutdown = null;
            ManagementClass mcWin32 = new ManagementClass("Win32_OperatingSystem");
            mcWin32.Get();

            // You can't shutdown without security privileges
            mcWin32.Scope.Options.EnablePrivileges = true;
            ManagementBaseObject mboShutdownParams =
                     mcWin32.GetMethodParameters("Win32Shutdown");

            // Flag 1 means we want to shut down the system. Use "2" to reboot.
            mboShutdownParams["Flags"] = "1";
            mboShutdownParams["Reserved"] = "0";
            foreach (ManagementObject manObj in mcWin32.GetInstances())
            {
                mboShutdown = manObj.InvokeMethod("Win32Shutdown",
                                               mboShutdownParams, null);
            }
        }

From here

And the rest is just a loop to check if the file exists

        ///

        /// The main entry point for the application.
        /// 

        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            while (true)
            {
                if (!System.IO.File.Exists("D:\\Shutdown"))
                {
                    Thread.Sleep(500);
                }
                else
                {
                    System.IO.File.Delete("D:\\Shutdown");
                    Shutdown();
                    return;
                }
            }
        }

That’s it, I run the application and it will wait until I create a file named ‘shutdown’ in D:\, it will perform shutdown and quit

Here’s the sample code and binary

From time to time, when you have some errors in your controls, Visual may just stop responding altogether and forces you to restart without any indicator on what happened and how to fix it. To overcome this, there is two things developers should keep in mind:

1. Check database and connection routines, make sure they are initialized properly or blocked from running by checking the special property DesignMode (available as Form.DesignMode and UserControl.DesignMode).
2. To see the cause of the error, you have to debug Visual Studio itself. When designer error happened to you, choose debug this program and start a new instance of Visual Studio. The second instance should give you the unhandled exception and the code location of the error.