Output Console.WriteLine from WPF Windows Applications to actual console

Question

Background: I am struggling to add command line and batch processing capabilities to an existing WPF Windows Application. When I detect some options at startup I su

Answer 1

A WPF application will not have a console by default, but you can easily create one for it and then write to it just like in a console app. I've used this helper class before:

public class ConsoleHelper
{
    /// <summary>
    /// Allocates a new console for current process.
    /// </summary>
    [DllImport("kernel32.dll")]
    public static extern Boolean AllocConsole();

    /// <summary>
    /// Frees the console.
    /// </summary>
    [DllImport("kernel32.dll")]
    public static extern Boolean FreeConsole();
}

To use this in your example, you should be able to do this:

namespace WpfConsoleTest
{
    public partial class App : Application
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            ConsoleHelper.AllocConsole(); 
            Console.WriteLine("Start");
            System.Threading.Thread.Sleep(1000);
            Console.WriteLine("Stop");
            ConsoleHelper.FreeConsole();
            Shutdown(0);
        }
    }
}

And now, if you run it from the command line, you should see "Start" and "Stop" written to the console.

Answer 2

In the project properties, you can change the project type from a Windows application to a Console application, and AFAIK the only difference is that you get a console to use throughout the application's lifetime. I haven't tried it with WPF though.

If you want to open and close a console, you should use Alloc/FreeConsole, but it is usually simpler to change the project type.

Answer 3

After digging up a bit, I found this answer. The code is now:

namespace WpfConsoleTest
{
    public partial class App : Application
    {
        [DllImport("Kernel32.dll")]
        public static extern bool AttachConsole(int processId);

        protected override void OnStartup(StartupEventArgs e)
        {
            AttachConsole(-1);
            Console.WriteLine("Start");
            System.Threading.Thread.Sleep(1000);
            Console.WriteLine("Stop");
            Shutdown(0);
        }
    }
}

Calling the exe directly still has a nasty side effect, connected with the call returning immediately:

C:\test>WpfConsoleTest.exe

C:\test>Start
Stop

^^^^
The cursor will stay here waiting for the user to press enter!

The solution is, once again, to use start:

C:\test>start /wait WpfConsoleTest.exe
Start
Stop

Thanks for input!

Answer 4

What I've done in the past is to make it a console application and call P/Invoke to hide the app's associated Console window once I've shown my WPF Window:

//added using statements per comments...
using System.Diagnostics;
using System.Runtime.InteropServices;

    internal sealed class Win32
    {
        [DllImport("user32.dll")]
        static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

        public static void HideConsoleWindow()
        {
            IntPtr hWnd = Process.GetCurrentProcess().MainWindowHandle;

            if (hWnd != IntPtr.Zero)
            {
                ShowWindow(hWnd, 0); // 0 = SW_HIDE
            }
        }
    }