How to show the console on a C# program with Windows application output type

Question

I have a C# Console application project where the output type is set to "Windows application". This is so the console does not flash up at the start of the program.

However i also want to allow a help command line argument which will display details about the program if you run it from the command line with "/?" as an argument.

Is there a way to have the program run as a windows application normally but show a console if the help argument is passed?

EDIT - After reading the answers and a similar one at This question (this question assumes you are running with a console application output type) I am using this solution.

  [DllImport(Kernel32_DllName)]
    private static extern bool AllocConsole();

    [DllImport("kernel32.dll")]
    static extern IntPtr GetConsoleWindow();

    [DllImport("user32.dll")]
    static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

    const int SW_HIDE = 0;
    const int SW_SHOW = 5;

  static void Main(string[] args)
    {

        if(args.Contains("/?"))
        {
           AllocConsole();

           Console.WriteLine("helpText");
           Console.ReadLine();


           var handle = GetConsoleWindow();

          //Hides console
           ShowWindow(handle, SW_HIDE);
        }
 }

Answer 1

I have not found a way to do exactly as you are asking, but you can have a console open up depending on the input. For example:

class Program
{
    private const string Kernel32_DllName = "kernel32.dll";

    [DllImport(Kernel32_DllName)]
    private static extern bool AllocConsole();
    static void Main(string[] args)
    {

        if (args[0] == "/")
        {
            AllocConsole();


            Console.WriteLine("Details");
            Console.ReadKey();
            //cases and such for your menu options
        }

That will open a console that you can use if you follow the run command with a / even though the output type of the project is a Windows Application.

Answer 2

Is there a way to have the program run as a windows application normally but show a console if the help argument is passed?

For what you want, learn about using command line arguments here. Basically declare Main to accept arguments as an array of string:

static void Main(string[] args)

Use a simple dialog form to display the help message or even a MessageBox which is a very simple dialog form.

This gives you much better control rather than trying to cobble something together that wasn't really meant to be put together.

Answer 3

When I need to do stuff like this, I usually make my app a console app. I then parse the args if any in main and decide if I'm going to hide the console window and launch my UI or write to the console.

Hiding a window is fairly straightforward. See How to hide / unhide a process in C#? for an example.