C#：文件、文件夹特别操作

1、过滤特殊字符

    public class CharService:IDisposable
    {
        private List<char> _invalidChars;
        public CharService()
        {
            _invalidChars = new List<char>();
            _invalidChars.AddRange(Path.GetInvalidFileNameChars());
            _invalidChars.AddRange(Path.GetInvalidPathChars());
        }

        /// <summary>
        /// 特殊字符过滤
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public string SplitStringInvaild(string str,bool isLower=true)
        {
            str = ToDBC(str);
            StringBuilder sb = new StringBuilder();
            foreach (char c in str)
            {
                if (_invalidChars.Contains(c))
                    continue;

                if(isLower)
                    sb.Append(ToLower(c));
                else
                    sb.Append(c);
            }
            str = sb.ToString().Trim();
            if (isLower)
            {
                if (str.Substring(str.Length-,)==".")
                {
                    str = str.Substring(, str.Length - );
                }
            }
            return str;
        }

        public static char ToLower(char c)
        {
            if (('A' <= c) && (c <= 'Z'))
            {
                c = (char)(c | ' ');
            }
            return c;
        }

        public static String ToDBC(String input)
        {
            char[] c = input.ToCharArray();
            for (int i = ; i < c.Length; i++)
            {
                if (c[i] == )
                {
                    c[i] = (char);
                    continue;
                }
                if (c[i] >  && c[i] < )
                    c[i] = (char)(c[i] - );
            }
            return new String(c);
        }

        public void Dispose()
        {
            _invalidChars = null;
        }
    }

2、将DataTable数据保存为.csv文件

 private bool DataTableToCsv(System.Data.DataTable tb, string FileName)
        {
            bool Export = false;
            TextWriter writer = null;
            try
            {
                string text = String.Empty;
                // 使用指定编码和缓冲区大小，为指定路径上的指定文件初始化 StreamWriter 类的新实例。
                // 如果该文件存在，则可以将其覆盖或向其追加。如果该文件不存在，则此构造函数将创建一个新文件。
                writer = new StreamWriter(FileName, false, Encoding.UTF8);

                // 取得列的个数
                int count = tb.Columns.Count;
                string[] fields = new string[count];
                // 循环添加列名
                for (int i = ; i < count; i++)
                {
                    DataColumn column = tb.Columns[i];

                    fields[i] = column.ColumnName;

                }
                text = string.Join(",", fields);
                writer.WriteLine(text);
                // 遍历行
                foreach (DataRow row in tb.Rows)
                {
                    // 给每一行添加列单元
                    for (int i = ; i < count; i++)
                    {
                        if (row[i] == null)
                        {
                            fields[i] = String.Empty;
                            continue;
                        }
                        if (row[i] == DBNull.Value)
                        {
                            fields[i] = String.Empty;
                            continue;
                        }
                        string field = row[i].ToString();
                        // CSV格式有规定,比如,如果字段中有逗号、双引号、回车换行符、前或后置空格,
                        // 必须把字段用双引号扩起来,如果文本中有双引号，必须用两个双引号替换
                        field = field.Replace("\"", "\"\"");
                        if (field.IndexOf(',') >= )
                        {
                            fields[i] = string.Format("\"{0}\"", field);
                            continue;
                        }
                        if (field.IndexOf('\r') >= )
                        {
                            fields[i] = string.Format("\"{0}\"", field);
                            continue;
                        }
                        if (field.IndexOf('\n') >= )
                        {
                            fields[i] = string.Format("\"{0}\"", field);
                            continue;
                        }
                        if (field.IndexOf('\"') >= )
                        {
                            fields[i] = string.Format("\"{0}\"", field);
                            continue;
                        }
                        if (field != field.Trim())
                        {
                            fields[i] = string.Format("\"{0}\"", field);
                            continue;
                        }
                        fields[i] = (i == ) ? DateTime.Parse(row[i].ToString()).ToString("yyyy/MM/dd HH:mm:ss") : row[i].ToString();
                    }
                    text = string.Join(",", fields);
                    writer.WriteLine(text);
                }
                _logServ.Debug("导出成功");
                //Console.WriteLine("导出成功", "提示");
                Export = true;
            }
            catch (Exception ex)
            {
                _logServ.Error("导出失败" + ex.Message);
                // Console.WriteLine("导出失败" + ex.Message, "提示");
                Export = false;
            }
            finally
            {
                if (writer != null)
                {
                    writer.Close();
                }
            }
            return Export;
        }

3、+过滤掉非法字符

        /// <summary>
        /// 过滤掉非法字符和点字符
        /// </summary>
        /// <param name="directoryName"></param>
        /// <returns></returns>
        public String DirectoryNameFilter(String directoryName)
        {
            string invalidChars = "\\/:*?\"<>|.";    //自定义非法字符（比系统的多了个.）
            foreach (char c in invalidChars)
            {
                directoryName.Replace(c.ToString(), string.Empty);
            }
            return directoryName;
        }

        /// <summary>
        /// 过滤掉非法字符
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        public String NameFilter(String name)
        {
            string invalidChars = "\\/:*?\"<>|";    //自定义非法字符（比系统的多了个.）
            foreach (char c in invalidChars)
            {
                name.Replace(c.ToString(), string.Empty);
            }
            return name;
        }

4、计算文件夹大小

        #region 计算文件夹大小

        /// <summary>
        /// 计算文件夹大小
        /// </summary>
        /// <param name="dirPath">文件夹</param>
        /// <returns></returns>
        public long CalculateDirSize(string dirPath)
        {
            long sumSize = ;
            try
            {
                if (!Directory.Exists(dirPath))
                {
                    DirectoryInfo dirInfo = new DirectoryInfo(dirPath);
                    FileInfo[] files = dirInfo.GetFiles();
                    foreach (FileInfo fInfo in files)
                    {
                        sumSize += fInfo.Length;
                    }
                    DirectoryInfo[] dirs = dirInfo.GetDirectories();
                    foreach (DirectoryInfo dInfo in dirs)
                    {
                        sumSize += CalculateDirSize(dInfo.FullName);
                    }
                }
            }
            catch (Exception ex)
            {
                LogHelper.Instance.Error("计算文件夹大小(" + dirPath + ")出错：" + ex.Message);
            }
            return sumSize;
        }