Windows Service can not open Windows Form - winforms

Question

I am trying to create a Windows Service using TopShelf and within this service i want to launch a Windows Form.After i created the service and i debugged it calling ShowDialog the form does not show up:
Service
class SimpleServ {
private Task task;
private const string PATH = #"D:/out.txt";
private Logger logger;
private CancellationTokenSource src = new CancellationTokenSource();
public SimpleServ() {
logger = new Logger();
}
public void Start() {
logger.Log("Started");
this.task = Task.Run(async () => {
var fm = new Fm(logger);
while (true) {
fm.ShowDialog();
logger.Log("Just closed the dialog");
await Task.Delay(3000);
}
});
}
public void Stop() {
logger.Log("Stopped service");
}
}
Form
public partial class Fm : Form {
private Logger log;
public Fm(Logger log) {
this.log = log;
this.log.Log("From Form constructor");
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e) {
this.log.Log("Button clicked");
this.Close();
}
}
Main
class Program {
static void Main(string[] args) {
var exitCode = HostFactory.Run(x => {
x.Service<SimpleServ>(s => {
s.ConstructUsing(h => new SimpleServ());
s.WhenStarted(h => h.Start());
s.WhenStopped(h => h.Stop());
});
x.RunAsLocalSystem();
x.SetServiceName("SimpleService");
x.SetDisplayName("Simple Service");
x.SetDescription("Simple serv description");
});
int exitCodeValue = (int)Convert.ChangeType(exitCode, exitCode.GetTypeCode());
Environment.ExitCode = exitCodeValue;
}
}
I have attached myself to the service and after it reaches the line of ShowDialog nothing happens.
Update
I have also added a Logger to log all important events and so far , it seems the form opens but i can not see it:
Logger
public class Logger {
private string path;
public Logger(string logPath=Constants.PATH) {
this.path = logPath;
}
private object #lock = new object();
public void Log(string message) {
string formattedMessage = "Date:" + DateTime.Now.ToString() + "\tMessage:" + message;
File.AppendAllLines(this.path, new string[] { formattedMessage });
}
}
The output of the file is :
Date:6/12/2019 11:19:13 AM Message:Started
Date:6/12/2019 11:19:13 AM Message:From Form constructor

Answer 1

In a world where Session 0 Isolation -- an important security measure to prevent Shatter attacks -- is the law of the land, you should think very carefully about any design relying on service interaction.
A best practice is to restructure your solution to have:
A service that runs in the background, independently of the
user
A conventional GUI application that interacts with the service and
can be run by any user