How to write c# service that I can also run as a winforms program?

Question

I have a windows service written in C# that acts as a proxy for a bunch of network devices to the back end database. For testing and also to add a simulation layer to test the back end I would like to have a GUI for the test operator to be able run the simulation. Also for a striped down version to send out as a demo. The GUI and service do not have to run at the same time. What is the best way to achieve this duel operation?

Edit: Here is my solution combing stuff from this question , Am I Running as a Service and Install a .NET windows service without InstallUtil.exe using this excellent code by Marc Gravell

It uses the following line to test if to run the gui or run as service.

 if (arg_gui || Environment.UserInteractive || Debugger.IsAttached)

Here is the code.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.ComponentModel;
using System.ServiceProcess;
using System.Configuration.Install;
using System.Diagnostics;

namespace Form_Service
{
   static class Program
   {
      /// 
      /// The main entry point for the application.
      /// 
      [STAThread]
      static int Main(string[] args)
      {
         bool arg_install =  false;
         bool arg_uninstall = false;
         bool arg_gui = false;
         bool rethrow = false;
         try
         {
            foreach (string arg in args)
            {
               switch (arg)
               {
                  case "-i":
                  case "-install":
                     arg_install = true; break;
                  case "-u":
                  case "-uninstall":
                     arg_uninstall = true; break;
                  case "-g":
                  case "-gui":
                     arg_gui = true; break;
                  default:
                     Console.Error.WriteLine("Argument not expected: " + arg);
                     break;
               }
            }
            if (arg_uninstall)
            {
               Install(true, args);
            }
            if (arg_install)
            {
               Install(false, args);
            }
            if (!(arg_install || arg_uninstall))
            {
               if (arg_gui || Environment.UserInteractive || Debugger.IsAttached)
               {
                  Application.EnableVisualStyles();
                  Application.SetCompatibleTextRenderingDefault(false);
                  Application.Run(new Form1());
               }
               else
               {
                  rethrow = true; // so that windows sees error... 
                  ServiceBase[] services = { new Service1() };
                  ServiceBase.Run(services);
                  rethrow = false;
               }
            }
            return 0;
         }
         catch (Exception ex)
         {
            if (rethrow) throw;
            Console.Error.WriteLine(ex.Message);
            return -1;
         }
      }

      static void Install(bool undo, string[] args)
      {
         try
         {
            Console.WriteLine(undo ? "uninstalling" : "installing");
            using (AssemblyInstaller inst = new AssemblyInstaller(typeof(Program).Assembly, args))
            {
               IDictionary state = new Hashtable();
               inst.UseNewContext = true;
               try
               {
                  if (undo)
                  {
                     inst.Uninstall(state);
                  }
                  else
                  {
                     inst.Install(state);
                     inst.Commit(state);
                  }
               }
               catch
               {
                  try
                  {
                     inst.Rollback(state);
                  }
                  catch { }
                  throw;
               }
            }
         }
         catch (Exception ex)
         {
            Console.Error.WriteLine(ex.Message);
         }
      }
   }

   [RunInstaller(true)]
   public sealed class MyServiceInstallerProcess : ServiceProcessInstaller
   {
      public MyServiceInstallerProcess()
      {
         this.Account = ServiceAccount.NetworkService;
      }
   }

   [RunInstaller(true)]
   public sealed class MyServiceInstaller : ServiceInstaller
   {
      public MyServiceInstaller()
      {
         this.Description = "My Service";
         this.DisplayName = "My Service";
         this.ServiceName = "My Service";
         this.StartType = System.ServiceProcess.ServiceStartMode.Manual;
      }
   }

}

Answer 1

You basically have two choices. Either expose an API on the service which you can then call from the UI app OR enable the service to run either as a winforms app or a service.

The first option is pretty easy - use remoting or WCF to expose the API.

The second option can be achieved by moving the "guts" of your app into a separate class then create a service wrapper and a win-forms wrapper that both call into your "guts" class.

static void Main(string[] args)
{
    Guts guts = new Guts();

    if (runWinForms)
    {
        System.Windows.Forms.Application.EnableVisualStyles();
        System.Windows.Forms.Application.SetCompatibleTextRenderingDefault(false);

        FormWrapper fw = new FormWrapper(guts);

        System.Windows.Forms.Application.Run(fw);
    }
    else
    {
        ServiceBase[] ServicesToRun;
        ServicesToRun = new ServiceBase[] { new ServiceWrapper(guts) };
        ServiceBase.Run(ServicesToRun);
    }
}

Answer 2

Create a new winforms app the references the assembly of your service.