protected override void OnLoad(EventArgs e) { base.OnLoad(e); var patternLayout = new PatternLayout(); patternLayout.AddConverter("rfc3339", typeof(Rfc3339Converter)); patternLayout.ConversionPattern = "%rfc3339 %level %message%newline"; patternLayout.ActivateOptions(); var a = new TextboxAppender(this.textBoxProgress) { Layout = patternLayout, Threshold = Level.Debug, Name = textBoxProgress.Name, }; a.ActivateOptions(); appender = a; ((Hierarchy)log4net.LogManager.GetRepository()).Root.AddAppender(appender); }