C#如何在运行时找到WCF IIS部署/虚拟目录来更改日志文件的名称？

string virtualDirectoryPath = System.Web.Hosting.HostingEnvironment.ApplicationVirtualPath;

string logFilePath = System.IO.Path.Combine(virtualDirectoryPath, "Logs");

string logFileName = System.IO.Path.Combine(logFilePath, "log_" + DateTime.Now.ToString("yyyyMMdd") + ".txt");

using (System.IO.StreamWriter writer = new System.IO.StreamWriter(logFileName, true))
{
    writer.WriteLine("日志内容");
}

string virtualDirectoryPath = System.Web.Hosting.HostingEnvironment.ApplicationVirtualPath;
string logFilePath = System.IO.Path.Combine(virtualDirectoryPath, "Logs");
string logFileName = System.IO.Path.Combine(logFilePath, "log_" + DateTime.Now.ToString("yyyyMMdd") + ".txt");

using (System.IO.StreamWriter writer = new System.IO.StreamWriter(logFileName, true))
{
    writer.WriteLine("日志内容");
}