写错误日志

public void WriteMessage(string filename, string message, string method)
        {
            string path = GetAssemblyPath() + @"\errorlog.txt";
            FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            using (StreamWriter sw = new StreamWriter(fs))
            {
                sw.BaseStream.Seek(0, SeekOrigin.End);
                StringBuilder sb = new StringBuilder();
                sb.Append("时间：");
                sb.Append(DateTime.Now);
                sb.Append("      文件：");
                sb.Append(filename + "     ");
                sb.Append("方法:" + method);
                sb.Append("     内容：");
                sb.Append(message);
                sw.WriteLine(sb);
                sw.Flush();
                sw.Close();
                fs.Close();
            }
        }

private string GetAssemblyPath()        

{            

           string _CodeBase = System.Reflection.Assembly.GetExecutingAssembly().CodeBase;

           _CodeBase = _CodeBase.Substring(8, _CodeBase.Length - 8);    // 8是 file:// 的长度

           string[] arrSection = _CodeBase.Split(new char[] { '/' });

           string _FolderPath = "";           

           for (int i = 0; i < arrSection.Length - 1; i++)           

{               

      _FolderPath += arrSection[i] + "/";      

}

           return _FolderPath;    

}