在开发，有时为了验证程序运行是否正确，通常要写日志来记录操作，在一个日志类里，通常有两个方法：

1、以日期作为日志文件的名称

public void WriteLog(string msg)  
{  
    string filePath = AppDomain.CurrentDomain.BaseDirectory + "Log";  
    if (!Directory.Exists(filePath))  
    {  
        Directory.CreateDirectory(filePath);  
    }  
    string logPath = AppDomain.CurrentDomain.BaseDirectory + "Log\\" + DateTime.Now.ToString("yyyy-MM-dd") + ".txt";  
    try  
    {  
        using (StreamWriter sw = File.AppendText(logPath))  
        {  
            sw.WriteLine("消息：" + msg);  
            sw.WriteLine("时间：" + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"));  
            sw.WriteLine("**************************************************");  
            sw.WriteLine();  
            sw.Flush();  
            sw.Close();  
            sw.Dispose();  
        }  
    }  
    catch (IOException e)  
    {  
        using (StreamWriter sw = File.AppendText(logPath))  
        {  
            sw.WriteLine("异常：" + e.Message);  
            sw.WriteLine("时间：" + DateTime.Now.ToString("yyy-MM-dd HH:mm:ss"));  
            sw.WriteLine("**************************************************");  
            sw.WriteLine();  
            sw.Flush();  
            sw.Close();  
            sw.Dispose();  
        }  
    }  
}  

2、以文档名称和日期结合作为文件名

public void WriteLog(string documentName, string msg)  
{  
    string errorLogFilePath = System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Log");  
    if (!System.IO.Directory.Exists(errorLogFilePath))  
    {  
        System.IO.Directory.CreateDirectory(errorLogFilePath);  
    }  
    string logFile = System.IO.Path.Combine(errorLogFilePath, documentName + "@" + DateTime.Today.ToString("yyyy-MM-dd") + ".txt");  
    bool writeBaseInfo = System.IO.File.Exists(logFile);  
    StreamWriter swLogFile = new StreamWriter(logFile, true, Encoding.Unicode);  
    swLogFile.WriteLine(DateTime.Now.ToString("HH:mm:ss") + "\t" + msg);  
    swLogFile.Close();  
    swLogFile.Dispose();  
}