使用 log4net 的 RichTextBoxAppender

有没有办法使用 log4net 以编程方式创建 RichTextBox Appender？ 换句话说，没有 xml app.config？

using System;
using System.Windows.Forms;
using System.Drawing;

using log4net;
using log4net.Core;
using log4net.Appender;
using log4net.Util;

namespace Vip.Logging
{
    /// <summary>
    /// Description of RichTextBoxAppender.
    /// </summary>
    public class RichTextBoxAppender : AppenderSkeleton
    {
        #region Private Instance Fields
        private RichTextBox richTextBox = null;
        private Form containerForm = null;
        private LevelMapping levelMapping = new LevelMapping();
        private int maxTextLength = 100000;
        #endregion

        private delegate void UpdateControlDelegate(LoggingEvent loggingEvent);

        #region Constructor
        public RichTextBoxAppender(RichTextBox myRichTextBox) : base()
        {
            richTextBox = myRichTextBox;
            containerForm = (Form)richTextBox.Parent;
        }
        #endregion

        private void UpdateControl(LoggingEvent loggingEvent)
        {
            // There may be performance issues if the buffer gets too long
            // So periodically clear the buffer
            if (richTextBox.TextLength > maxTextLength)
            {
                richTextBox.Clear();
                richTextBox.AppendText(string.Format("(Cleared log length max: {0})\n", maxTextLength));
            }

            // look for a style mapping
            LevelTextStyle selectedStyle = levelMapping.Lookup(loggingEvent.Level) as LevelTextStyle;
            if (selectedStyle != null)
            {
                // set the colors of the text about to be appended
                richTextBox.SelectionBackColor = selectedStyle.BackColor;
                richTextBox.SelectionColor = selectedStyle.TextColor;

                // alter selection font as much as necessary
                // missing settings are replaced by the font settings on the control
                if (selectedStyle.Font != null)
                {
                    // set Font Family, size and styles
                    richTextBox.SelectionFont = selectedStyle.Font;
                }
                else if (selectedStyle.PointSize > 0 && richTextBox.Font.SizeInPoints != selectedStyle.PointSize)
                {
                    // use control's font family, set size and styles
                    float size = selectedStyle.PointSize > 0.0f ? selectedStyle.PointSize : richTextBox.Font.SizeInPoints;
                    richTextBox.SelectionFont = new Font(richTextBox.Font.FontFamily.Name, size, selectedStyle.FontStyle);
                }
                else if (richTextBox.Font.Style != selectedStyle.FontStyle)
                {
                    // use control's font family and size, set styles
                    richTextBox.SelectionFont = new Font(richTextBox.Font, selectedStyle.FontStyle);
                }
            }
            richTextBox.AppendText(RenderLoggingEvent(loggingEvent));
        }

        protected override void Append(LoggingEvent LoggingEvent)
        {
            if (richTextBox.InvokeRequired)
            {
                richTextBox.Invoke(
                    new UpdateControlDelegate(UpdateControl),
                    new object[] { LoggingEvent });
            }
            else
            {
                UpdateControl(LoggingEvent);
            }
        }

        public void AddMapping(LevelTextStyle mapping)
        {
            levelMapping.Add(mapping);
        }

        public override void ActivateOptions()
        {
            base.ActivateOptions();
            levelMapping.ActivateOptions();
        }

        protected override bool RequiresLayout { get { return true; } }
    }

    public class LevelTextStyle : LevelMappingEntry
    {
        private Color textColor;
        private Color backColor;
        private FontStyle fontStyle = FontStyle.Regular;
        private float pointSize = 0.0f;
        private bool bold = false;
        private bool italic = false;
        private string fontFamilyName = null;
        private Font font = null;

        public bool Bold { get { return bold; } set { bold = value; } }
        public bool Italic { get { return italic; } set { italic = value; } }
        public float PointSize { get { return pointSize; } set { pointSize = value; } }

        /// <summary>
        /// Initialize the options for the object
        /// </summary>
        /// <remarks>Parse the properties</remarks>
        public override void ActivateOptions()
        {
            base.ActivateOptions();
            if (bold) fontStyle |= FontStyle.Bold;
            if (italic) fontStyle |= FontStyle.Italic;

            if (fontFamilyName != null)
            {
                float size = pointSize > 0.0f ? pointSize : 8.25f;
                try
                {
                    font = new Font(fontFamilyName, size, fontStyle);
                }
                catch (Exception)
                {
                    font = new Font("Arial", 8.25f, FontStyle.Regular);
                }
            }
        }

        public Color TextColor { get { return textColor; } set { textColor = value; } }
        public Color BackColor { get { return backColor; } set { backColor = value; } }
        public FontStyle FontStyle { get { return fontStyle; } set { fontStyle = value; } }
        public Font Font { get { return font; } set { font = value; } }
    }
}




public partial class MainForm : Form
{
    private static string locPath = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
    private static string dskPath = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory);
    private RichTextBoxAppender rba;
    private MessageBoxAppender mba;

    public MainForm()
    {
        InitializeComponent();

        if (!Global.logger.Logger.Repository.Configured)
        {
            rba = new RichTextBoxAppender(richTextBoxLog);
            rba.Threshold = Level.All;
            rba.Layout = new PatternLayout("%date{dd-MM-yyyy HH:mm:ss.fff} %5level %message %n");
            LevelTextStyle ilts = new LevelTextStyle();
            ilts.Level = Level.Info;
            ilts.TextColor = Color.Yellow;
            ilts.PointSize = 10.0f;
            rba.AddMapping(ilts);
            LevelTextStyle dlts = new LevelTextStyle();
            dlts.Level = Level.Debug;
            dlts.TextColor = Color.LightBlue;
            dlts.PointSize = 10.0f;
            rba.AddMapping(dlts);
            LevelTextStyle wlts = new LevelTextStyle();
            wlts.Level = Level.Warn;
            wlts.TextColor = Color.Chartreuse;
            wlts.PointSize = 10.0f;
            rba.AddMapping(wlts);
            LevelTextStyle elts = new LevelTextStyle();
            elts.Level = Level.Error;
            elts.TextColor = Color.Crimson;
            elts.BackColor = Color.Cornsilk;
            elts.PointSize = 10.0f;
            rba.AddMapping(elts);

            BasicConfigurator.Configure(rba);
            rba.ActivateOptions();

            mba = new MessageBoxAppender();
            mba.Layout = new PatternLayout("%date{dd-MM-yyyy HH:mm:ss.fff} %5level %message %n");
            mba.Threshold = Level.Error;
            BasicConfigurator.Configure(mba);
            mba.ActivateOptions();

            RollingFileAppender fa = new RollingFileAppender();
            fa.AppendToFile = true;
            fa.Threshold = log4net.Core.Level.All;
            fa.RollingStyle = RollingFileAppender.RollingMode.Size;
            fa.MaxFileSize = 100000;
            fa.MaxSizeRollBackups = 3;
            fa.File = dskPath + @"\FgPleoraLog.txt";
            fa.Layout = new log4net.Layout.PatternLayout("%date{dd-MM-yyyy HH:mm:ss.fff} %5level %message (%logger{1}:%line)%n");
            log4net.Config.BasicConfigurator.Configure(fa);
            fa.ActivateOptions();
        }
    }