写日志文件

bool WriteTxtFile(string filename, string content)
{
    bool bRet = false;
    FileStream fs = null;
    StreamWriter sw = null;

    try
    {
        FileInfo fi = new FileInfo(filename);
        if (!fi.Directory.Exists)
        {
            Directory.CreateDirectory(fi.Directory.FullName);
        }
                
        //fs = new FileStream(filename, FileMode.Create, FileAccess.Write);
        fs = new FileStream(filename, FileMode.Append, FileAccess.Write);
        sw = new StreamWriter(fs, Encoding.Default);
        //DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:fff:ffffff"))
        string s = string.Format("{0} {1}\n", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:fff"), content);
        sw.Write(s);
        sw.Flush();
        bRet = true;
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
    finally
    {
        if (sw != null)
            sw.Close();
        if (fs != null)
            fs.Close();
    }

    return bRet;
}