Adding console appender to a windows form in log4net

问题

Is it possible to add a console to a form based C# application ? Currently when I do something like

Console.WriteLine("testing");

It appears in output window of the VS2010. I want to know if its possible to attach a console to my windows form application.So that the output appears in the console.

EDIT: Looks like my first question was a bit misleading and it did not exactly specify what I wanted to accomplish. I just added a console to my application using

    [DllImport("kernel32")]
    static extern int AllocConsole();

However what I really want is the output of log4net console appender to be displayed in that console which is not happening. The xml for my appender is

  <appender name="ColoredConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
    <mapping>
      <level value="INFO" />
      <foreColor value="White" />
      <backColor value="Red, HighIntensity" />
    </mapping>
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%class %date - %message %newline" />
    </layout>
  </appender>

now when I go like

 log.info("Some log");

It still does not display it in the newly added console window. Any suggestions on how i could do that ?

回答1:

Just make your project a console application and create/show a form from the console application rather than the other way around.

回答2:

Just to throw it out there, be sure that you AllocConsole() before you load your log4net configuration. I tried doing something similar to what your question asks, and had the same problem before moving my call to AllocConsole. Once I moved it, log4net automatically wrote to the console that I allocated.

Essentially ... (and remember to do all your regular error checking not included here) ...

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace SampleApp
{
    class Program
    {
        [DllImport("kernel32.dll", SetLastError=true, CallingConvention=CallingConvention.Winapi)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool AllocConsole();

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

        [STAThread]
        private static void Main(string[] args)
        {
            // (1) Make sure we have a console to use.
            Program.AllocConsole();
            try {
                // (2) Tell log4net to configure itself according to our app.config data.
                log4net.Config.XmlConfigurator.Configure();
                // (3) Usual WinForms startup code here.
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new SampleApp.Form1());
            } catch ( Exception ) {
                // WAT!
            }
            // (4) Remember to release the console before we exit.
            Program.FreeConsole();
        }
    }
}

Not 100% sure why it makes a difference as to when the console is allocated, but this did fix the problem for me.

来源：https://stackoverflow.com/questions/14863282/adding-console-appender-to-a-windows-form-in-log4net

标签

log4net