C#程序中进行打印输出文本

1.添加LogHelpter类

public class LogHelpter
{
    /// <summary>
    /// 最多记录30个日志文件，其他的删除历史文件
    /// </summary>
    const int MAX_FILE_COUNT = 30;

    /// <summary>
    /// 文件保存的目录
    /// </summary>
    static string fileSaveDir = "";

    /// <summary>
    /// 限制文件生成大小，1024000字节,大约1024kb，1M
    /// </summary>
    const long fileBytes = 1024000;

    //日志文件保存根路径   
    const string saveFolder = "MesLogs";

    private readonly static object lockObj = new object();

    static LogHelpter()
    {
        //删除超过指定数量的历史文件    
        Task.Run(() =>
        {
            while (true)
            {
                try
                {
                    //自动删除文件，
                    string[] filePathArr = System.IO.Directory.GetFileSystemEntries(fileSaveDir);

                    if (filePathArr == null || filePathArr.Length == 0)
                    {
                        goto DO_SELEEP;
                    }
                    List<FileInfo> files = new List<FileInfo>();
                    foreach (var item in filePathArr)
                    {
                        //Console.WriteLine("日志文件：" + item);
                        System.IO.FileInfo fileInfo = new System.IO.FileInfo(item);
                        files.Add(fileInfo);
                    }
                    var del_files = files.OrderByDescending(g => g.LastWriteTime).Skip(MAX_FILE_COUNT);
                    if (del_files == null || del_files.Count() == 0)
                    {
                        goto DO_SELEEP;
                    }
                    foreach (var file in del_files)
                    {
                        file.Delete();
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine("LogHelpter执行删除文件功能异常," + ex.Message);
                }
            DO_SELEEP:
                System.Threading.Thread.Sleep(60000);
            }
        });

    }

    /// <summary>
    /// fileFolderPath为文件保存目录
    /// </summary>
    /// <param name="fileFolderPath">文件保存目录</param>
    /// <param name="fileNameNoExtension"></param>
    /// <param name="fileNamePrefix">文件名前缀</param>
    /// <returns></returns>
    static string GetNewFileName(string fileFolderPath, string fileNameNoExtension, string fileNamePrefix = null)
    {



        string fileName = string.Empty;

        //文件名前缀
        fileNamePrefix = string.IsNullOrWhiteSpace(fileNamePrefix) ? "" : fileNamePrefix;
        int index = 1;
        if (fileNameNoExtension.LastIndexOf('_') == -1)
        {
            // fileName = Path.Combine(fileFolderPath, fileNamePrefix + DateTime.Now.ToString("yyyy-MM-dd") + "_" + index + ".log");
        }
        else
        {
            var arr = fileNameNoExtension.Split('_');
            int.TryParse(arr[arr.Length - 1], out index);
            if (index == 0 || index > 900)
            {
                index = 1;
            }
        }
        fileName = Path.Combine(fileFolderPath, fileNamePrefix + DateTime.Now.ToString("yyyy-MM-dd") + "_" + index + ".log");
        while (File.Exists(fileName))
        {
            if (File.ReadAllBytes(fileName).Length < fileBytes)
            {
                break;
            }
            index++;
            fileName = Path.Combine(fileFolderPath, fileNamePrefix + DateTime.Now.ToString("yyyy-MM-dd") + "_" + index + ".log");
        }
        return fileName;
    }

    /// <summary>  
    /// 日志记录，在程序执行的根目录，写入txt文件，文件固定大小，超过限定大小自动创建新日志文件
    /// </summary>  
    /// <param name="msg">记录内容</param>  
    /// <param name="storeDir">文件保存文件夹</param>  
    /// <param name="fileNamePrefix">文件名前缀_</param>  
    /// <returns></returns>  
    public static void AddLog(string msg, string storeDir = null, string fileNamePrefix = null)
    {
        //调用方法：LogHelpter.AddLog("这是日志文件");
        if (FormIsSave.IS_SAVE_LOG == true)  //如果保存开关开启，则保存日志
        {
            //Console.WriteLine(DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff") + " " + msg);
            lock (lockObj)
            {
                try
                {
                    //文件名前缀
                    fileNamePrefix = string.IsNullOrWhiteSpace(fileNamePrefix) ? "" : fileNamePrefix + "_";

                    string fileFolderPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, saveFolder);
                    //日志路径，当前绝对路径，例如：E:\Windows\bin\Release\DXLogs
                    //string fileFolderPath =@"C:\DXLogs";  //写指定目录

                    if (!string.IsNullOrWhiteSpace(storeDir))
                    {
                        fileFolderPath = Path.Combine(fileFolderPath, storeDir);
                    }
                    if (Directory.Exists(fileFolderPath) == false)
                    {
                        Directory.CreateDirectory(fileFolderPath);
                    }
                    fileSaveDir = fileFolderPath;
                    string fileName = string.Empty;

                    string[] files = Directory.GetFiles(fileFolderPath);
                    if (files.Length == 0)
                    {
                        fileName = Path.Combine(fileFolderPath, fileNamePrefix + DateTime.Now.ToString("yyyy-MM-dd") + "_1.log");
                        goto DO_WRITE;
                    }
                    //string[] files2 = files.OrderByDescending(x => x).ToArray();
                    //string[] files2 = files.OrderByDescending(x => int.Parse(x.Substring(x.LastIndexOf("_")).Split("_")[1].Split(".")[0])).ToArray();
                    //string[] files2 = files.OrderByDescending(x => Regex.Matches(x, "_\\d*").Cast<string>().Last()).ToArray();
                    string[] files2 = files.OrderByDescending(x =>
                    {
                        var regList = Regex.Matches(x, "_\\d*");
                        return regList.Cast<Match>().Last().Value.TrimStart('_');
                    }).ToArray();

                    FileInfo fileInfo = new FileInfo(files2[0]);
                    string fileNameNoExtension = Path.GetFileNameWithoutExtension(fileInfo.Name);
                    fileName = GetNewFileName(fileFolderPath, fileNameNoExtension, fileNamePrefix);

                DO_WRITE:
                    FileStream fs = new FileStream(fileName, FileMode.Append, FileAccess.Write, FileShare.Write);
                    string msg2 = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff") + ">>" + msg + System.Environment.NewLine;
                    byte[] logBytes = UTF8Encoding.UTF8.GetBytes(msg2);
                    fs.Write(logBytes, 0, logBytes.Length);
                    fs.Flush();
                    fs.Close();
                    fs.Dispose();
                    //  tishiMsg = "写入日志成功"; 
                }
                catch (Exception ex)
                {
                    Console.WriteLine("LogHelpter日志写入异常：" + ex.ToString());
                }
            }
        }
    }


    public partial class FormIsSave
    {    /// <summary>
         /// 是否保存日志，true保存，false不保存。
         /// </summary>
        public static bool IS_SAVE_LOG = true;
    }
}

2.使用【在LogHelpter类中可改路径名和文件夹名】

LogHelpter.AddLog("open  App...");

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