Re: Problem using a ConsoleAppender in a Windows Form application

[Ron Grabowski]

ColoredConsoleAppender calls Console.OpenStandardOutput() in ActivateOptions to 
store a Stream that represents the console. When you create a console in a 
WinForm app you need to call ActivateOptions again so the internal Stream can 
be re-initialized:

public partial class Form1 : Form
{
    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool AllocConsole();

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool AttachConsole(int dwProcessId);

    public Form1()
    {
        InitializeComponent();

        var appender = new ColoredConsoleAppender();
        var mapping = new ColoredConsoleAppender.LevelColors
        {
            Level = Level.Debug,
            ForeColor = ColoredConsoleAppender.Colors.Red,
            BackColor = ColoredConsoleAppender.Colors.Blue
        };
        appender.AddMapping(mapping);
        appender.ActivateOptions();
        appender.Layout = new SimpleLayout();
        BasicConfigurator.Configure(appender);

        SetConsole();

        ILog log = LogManager.GetLogger(typeof(Form1));
        log.Debug("Hello World");
    }

    public static void SetConsole()
    {
        foreach (IAppender appender in 
LogManager.GetRepository().GetAppenders())
        {
            var coloredConsole = appender as ColoredConsoleAppender;

            if (coloredConsole != null)
            {
                if (AllocConsole())
                {
                    AttachConsole(-1);
                    coloredConsole.ActivateOptions();
                }

                return;
            }
        }
    }
}




________________________________
From: Michael SALOMON <michaelsalomo...@gmail.com>
To: log4net-user@logging.apache.org
Sent: Friday, June 26, 2009 9:21:31 AM
Subject: Problem using a ConsoleAppender in a Windows Form application

Hi !

I'm using log4net 1.2.10.0 and .NET 2.0

I wrote a Windows Form application and I want to be able to log debug messages 
in a ColoredConsoleAppender (or whatever type of Console appender).

If I compile my application as a Console Application, this works fine... If I 
compile it as a Windows Forms application, then I understand that no console is 
attached to my application, fair enough..

In this case I programmaticaly attach a brand new console by using this piece 
of code :

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool AllocConsole();

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool FreeConsole();

        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern bool AttachConsole(int dwProcessId);

        public static void SetConsole()
        {
            foreach (log4net.Appender.IAppender appender in 
log4net.LogManager.GetRepository().GetAppenders())
            {
                System.Type type = appender.GetType();

                if ((type == typeof(log4net.Appender.ColoredConsoleAppender))
                    || (type == typeof(log4net.Appender.ConsoleAppender)))
                {
                    if (AllocConsole())
                        AttachConsole(-1);

                    return;
                }
            }

So at startup, if any console appender is found, I attach a console...

At this stage, I can do things like : Console.WriteLine() , and it works very 
fine, I can see the messages in my new console...

But for some reason, the Console Appenders do not forward their messages to 
this console...

Do I miss something or do something wrong ?

I tried to create a custom appender that inherits ConsoleAppender and do 
something like:

protected override void Append (LoggingEvent loggingEvent)
{
    Console.WriteLine (RenderLoggingEvent(loggingEvent);
}

This works fine with my attached console, but I loose all the nice colored 
features... And fact is I do want them :)

Thanks a lot for your help

Michael