在运行时更改log4net转换模式或布局

是的,例如:

var appenders = log4net.LogManager.GetRepository().GetAppenders();
foreach (var rollingFileAppender in appenders.OfType<log4net.Appender.RollingFileAppender>())
{
     rollingFileAppender.Layout = new log4net.Layout.PatternLayout("- %message%newline");
}