Is it possible to have a WPF application print console output?

Question

I have a simple WPF application. Under normal use, App.xaml will launch MainWindow.xaml. But I would like to set it up so that if it is invoked with a special command line argument, that it will function as a console application instead.

So here's roughly what my App.xaml.cs file looks like:

using System;

namespace MyProject
{
    public partial class App : Application
    {
        public void App_OnStartup(object sender, StartupEventArgs e)
        {
            if (e.Args.Length == 1 && e.Args[0].Equals("/console"))
            {
                Console.WriteLine("this is a test");
                Environment.Exit(0);
            }
            else
            {
                var mainWindow = new MainWindow();
                mainWindow.Show();
            }
        }
    }
}

I would expect that when I run MyProject.exe /console from the command line, it would print the string "this is a test". But right now it doesn't print anything. How can I get it to work?

Answer 1

We have special class for this purpose:

internal static class ConsoleAllocator
{
    [DllImport(@"kernel32.dll", SetLastError = true)]
    static extern bool AllocConsole();

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

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

    const int SwHide = 0;
    const int SwShow = 5;


    public static void ShowConsoleWindow()
    {
        var handle = GetConsoleWindow();

        if (handle == IntPtr.Zero)
        {
            AllocConsole();
        }
        else
        {
            ShowWindow(handle, SwShow);
        }
    }

    public static void HideConsoleWindow()
    {
        var handle = GetConsoleWindow();

        ShowWindow(handle, SwHide);
    }
}

Just call ConsoleAllocator.ShowConsoleWindow() and then write to Console