Determine if .Net core console application is running in user interactive mode

To complement Martin Ullrich's helpful answer:

If you're willing to define user-interactive as runs in a console/terminal window visible to the current user, you can use the following approach (C#), which should work on all supported platforms:

Note: Visible means visible in principle, i.e., can be made visible by the user if currently obscured or minimized.

using System;
using System.Runtime.InteropServices;

namespace net.same2u.pg
{
  static class Program
  {
    // P/Invoke declarations for Windows.
    [DllImport("kernel32.dll")] static extern IntPtr GetConsoleWindow();
    [DllImport("user32.dll")] static extern bool IsWindowVisible(IntPtr hWnd);

    // Indicates if the current process is running:
    //  * on Windows: in a console window visible to the user.
    //  * on Unix-like platform: in a terminal window, which is assumed to imply
    //    user-visibility (given that hidden processes don't need terminals).
    public static bool HaveVisibleConsole()
    {
      return RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ?
                    IsWindowVisible(GetConsoleWindow())
                    :
                    Console.WindowHeight > 0;
    }

    static void Main(string[] args)
    {
      Console.WriteLine($"Running in visible console? {HaveVisibleConsole()}");
    }
  }
}

Note:

• On Windows, all console-mode applications always run in a console window, whether that window is visible or not; the P/Invoke function declarations check if the console window (GetConsoleWindow()) - if any - associated with the current process is a visible window (IsWindowVisible(), on the current user's desktop).

• On Unix-like platforms, non-GUI applications fundamentally don't need a terminal window to run, and launching such an application from a GUI app, for instance, does not involve a terminal. Therefore, the assumption is that if a terminal window is present at all, it implies that that window is visible; Console.WindowHeight only contains a positive value if a terminal window is present.

This probably will be fixed in some future version of .NET Core (maybe 5.0):

https://github.com/dotnet/runtime/issues/770 and https://github.com/dotnet/runtime/pull/1234

Meanwhile see other answers (e.g. Console.IsInputRedirected should work for detecting Windows Service context).

Another option is to check a process session id: for services it's always 0. So you can use the following snippet:

// Environment.UserInteractive is not working on NET Core 3.1
if (Process.GetCurrentProcess().SessionId != 0) 
{
    service.RunAsConsole(args);
}
else
{
    ServiceBase.Run(service);
}