如果您希望将日志文件放置在运行时将决定的指定位置，则该文件可能是您的项目输出目录，则可以配置以这种方式输入文件

If you want your log file to be place at a specified location which will be decided at run time may be your project output directory then you can configure your .config file entry in that way

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

，然后在调用log4net configure之前的代码中，按如下所示设置新路径

and then in the code before calling log4net configure, set the new path like below

 log4net.GlobalContext.Properties["LogFileName"] = @"E:\\file1"; //log file path
 log4net.Config.XmlConfigurator.Configure();

这有多简单? :)