CSV是逗号分隔值格式的文件,其文件以纯文本形式存储表格数据(数字和文本)。CSV文件由任意数目的记录组成,记录间以某种换行符分隔;每条记录由字段组成,字段间的分隔符是其它字符或字符串,最常见的是逗号或制表符。在C#中有时候需要读取和写入Csv文件,特此封装了一个工具类CsvHelper。特此说一句,C#将数据导出到CSV文件的速度比较快,有时候导出Excel文件很慢的时候可以选择先导出.csv文件,而后再本地用Excel软件打开。
CsvHelper类主要是利用C#操作Csv文件,主要包含2个方法。
dt2csv(参数略):将数据导入到csv文件中
csv2dt(参数略):将Csv读入DataTable
具体的工具类实现如下:
using System; using System.Collections.Generic; using System.Text; using System.IO; using System.Data; using System.Data.OleDb; namespace Core.IO { /// <summary> /// CSV文件转换类 /// </summary> public static class CsvHelper { /// <summary> /// 导出报表为Csv /// </summary> /// <param name="dt">DataTable</param> /// <param name="strFilePath">物理路径</param> /// <param name="tableheader">表头</param> /// <param name="columname">字段标题,逗号分隔</param> public static bool dt2csv(DataTable dt, string strFilePath, string tableheader, string columname) { try { string strBufferLine = ""; StreamWriter strmWriterObj = new StreamWriter(strFilePath, false, System.Text.Encoding.UTF8); strmWriterObj.WriteLine(tableheader); strmWriterObj.WriteLine(columname); for (int i = 0; i < dt.Rows.Count; i++) { strBufferLine = ""; for (int j = 0; j < dt.Columns.Count; j++) { if (j > 0) strBufferLine += ","; strBufferLine += dt.Rows[i][j].ToString(); } strmWriterObj.WriteLine(strBufferLine); } strmWriterObj.Close(); return true; } catch { return false; } } /// <summary> /// 将Csv读入DataTable /// </summary> /// <param name="filePath">csv文件路径</param> /// <param name="n">表示第n行是字段title,第n+1行是记录开始</param> public static DataTable csv2dt(string filePath, int n, DataTable dt) { StreamReader reader = new StreamReader(filePath, System.Text.Encoding.UTF8, false); int i = 0, m = 0; reader.Peek(); while (reader.Peek() > 0) { m = m + 1; string str = reader.ReadLine(); if (m >= n + 1) { string[] split = str.Split(','); System.Data.DataRow dr = dt.NewRow(); for (i = 0; i < split.Length; i++) { dr[i] = split[i]; } dt.Rows.Add(dr); } } return dt; } /// <summary> /// CSV转换成DataTable(OleDb数据库访问方式) /// </summary> /// <param name="csvPath">csv文件路径</param> /// <returns></returns> public static DataTable CSVToDataTableByOledb(string csvPath) { DataTable csvdt = new DataTable("csv"); if (!File.Exists(csvPath)) { throw new FileNotFoundException("csv文件路径不存在!"); } FileInfo fileInfo = new FileInfo(csvPath); using (OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileInfo.DirectoryName + ";Extended Properties='Text;'")) { OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM [" + fileInfo.Name + "]", conn); adapter.Fill(csvdt); } return csvdt; } /// <summary> /// CSV转换成DataTable(文件流方式) /// </summary> /// <param name="csvPath">csv文件路径</param> /// <returns></returns> public static DataTable CSVToDataTableByStreamReader(string csvPath) { DataTable csvdt = new DataTable("csv"); int intColCount = 0; bool blnFlag = true; DataColumn column; DataRow row; string strline = null; string[] aryline; using (StreamReader reader = new StreamReader(csvPath, FileEncoding.GetEncoding(csvPath))) { while (!string.IsNullOrEmpty((strline = reader.ReadLine()))) { aryline = strline.Split(new char[] { ',' }); if (blnFlag) { blnFlag = false; intColCount = aryline.Length; for (int i = 0; i < aryline.Length; i++) { column = new DataColumn(aryline[i]); csvdt.Columns.Add(column); } continue; } row = csvdt.NewRow(); for (int i = 0; i < intColCount; i++) { row[i] = aryline[i]; } csvdt.Rows.Add(row); } } return csvdt; } /// <summary> /// DataTable 生成 CSV /// </summary> /// <param name="dt">DataTable</param> /// <param name="csvPath">csv文件路径</param> public static void DataTableToCSV(DataTable dt, string csvPath) { if (null == dt) return; StringBuilder csvText = new StringBuilder(); StringBuilder csvrowText = new StringBuilder(); foreach (DataColumn dc in dt.Columns) { csvrowText.Append(","); csvrowText.Append(dc.ColumnName); } csvText.AppendLine(csvrowText.ToString().Substring(1)); foreach (DataRow dr in dt.Rows) { csvrowText = new StringBuilder(); foreach (DataColumn dc in dt.Columns) { csvrowText.Append(","); csvrowText.Append(dr[dc.ColumnName].ToString().Replace(',', ' ')); } csvText.AppendLine(csvrowText.ToString().Substring(1)); } File.WriteAllText(csvPath, csvText.ToString(), Encoding.Default); } } }