C# 動態放置log4net路徑

 參考網站logging - C# Log4Net - dynamically change log directory programmatically - Stack Overflow

config:

file type="log4net.Util.PatternString" value="%property{LogFileName}.txt"

程式碼：
log4net.GlobalContext.Properties["LogFileName"] = @"D:\abc";
log4net.Config.XmlConfigurator.Configure();