[C#] streamwriter亂碼問題

今天在將操作記錄寫入文字檔時，遇到寫入文字後的中文變成亂碼，目前找到的解決方案，Encoding.Default 可有效解決這個問題

public static void WriteTxtLog(string strLog, string Path, string FileName)
{
    StreamWriter txtwrite = default(StreamWriter);
    DirectoryInfo createdir = default(DirectoryInfo);
    FileInfo logfile = new FileInfo(Path + "\\" + FileName);
    //建log檔
    createdir = new DirectoryInfo(logfile.DirectoryName);
    if (createdir.Exists == false)
    {
        createdir.Create();
    }
    //使用與系統一致的編碼方式
    txtwrite = new StreamWriter(logfile.FullName, true, Encoding.Default);
    txtwrite.WriteLine(strLog);
    txtwrite.Close();
}