C# CSV文件讀寫

public class CSVFileHelper { /// <summary>
    /// 將DataTable中數據寫入到CSV文件中 /// </summary>
    /// <param name="dt">提供保存數據的DataTable</param>
    /// <param name="fileName">CSV的文件路徑</param>
    public static void SaveCSV(DataTable dt, string fullPath) { FileInfo fi = new FileInfo(fullPath); if (!fi.Directory.Exists) { fi.Directory.Create(); } FileStream fs = new FileStream(fullPath, System.IO.FileMode.Create, System.IO.FileAccess.Write); //StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.Default);
        StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.UTF8); string data = ""; //寫出列名稱
        for (int i = 0; i < dt.Columns.Count; i++) { data += dt.Columns[i].ColumnName.ToString(); if (i < dt.Columns.Count - 1) { data += ","; } } sw.WriteLine(data); //寫出各行數據
        for (int i = 0; i < dt.Rows.Count; i++) { data = ""; for (int j = 0; j < dt.Columns.Count; j++) { string str = dt.Rows[i][j].ToString(); str = str.Replace("\"", "\"\"");//替換英文冒號 英文冒號須要換成兩個冒號
                if (str.Contains(',') || str.Contains('"') || str.Contains('\r') || str.Contains('\n')) //含逗號 冒號 換行符的須要放到引號中
 { str = string.Format("\"{0}\"", str); } data += str; if (j < dt.Columns.Count - 1) { data += ","; } } sw.WriteLine(data); } sw.Close(); fs.Close(); DialogResult result = MessageBox.Show("CSV文件保存成功！"); if (result == DialogResult.OK) { System.Diagnostics.Process.Start("explorer.exe", Common.PATH_LANG); } } /// <summary>
    /// 將CSV文件的數據讀取到DataTable中 /// </summary>
    /// <param name="fileName">CSV文件路徑</param>
    /// <returns>返回讀取了CSV數據的DataTable</returns>
    public static DataTable OpenCSV(string filePath) { Encoding encoding = Common.GetType(filePath); //Encoding.ASCII;//         DataTable dt = new DataTable(); FileStream fs = new FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read); //StreamReader sr = new StreamReader(fs, Encoding.UTF8);
        StreamReader sr = new StreamReader(fs, encoding); //string fileContent = sr.ReadToEnd(); //encoding = sr.CurrentEncoding; //記錄每次讀取的一行記錄
        string strLine = ""; //記錄每行記錄中的各字段內容
        string[] aryLine = null; string[] tableHead = null; //標示列數
        int columnCount = 0; //標示是不是讀取的第一行
        bool IsFirst = true; //逐行讀取CSV中的數據
        while ((strLine = sr.ReadLine()) != null) { //strLine = Common.ConvertStringUTF8(strLine, encoding); //strLine = Common.ConvertStringUTF8(strLine);

            if (IsFirst == true) { tableHead = strLine.Split(','); IsFirst = false; columnCount = tableHead.Length; //建立列
                for (int i = 0; i < columnCount; i++) { DataColumn dc = new DataColumn(tableHead[i]); dt.Columns.Add(dc); } } else { aryLine = strLine.Split(','); DataRow dr = dt.NewRow(); for (int j = 0; j < columnCount; j++) { dr[j] = aryLine[j]; } dt.Rows.Add(dr); } } if (aryLine != null && aryLine.Length > 0) { dt.DefaultView.Sort = tableHead[0] + " " + "asc"; } sr.Close(); fs.Close(); return dt; } }

/// 給定文件的路徑，讀取文件的二進制數據，判斷文件的編碼類型 /// <param name="FILE_NAME">文件路徑</param>
/// <returns>文件的編碼類型</returns>
 
public static System.Text.Encoding GetType(string FILE_NAME) { System.IO.FileStream fs = new System.IO.FileStream(FILE_NAME, System.IO.FileMode.Open, System.IO.FileAccess.Read); System.Text.Encoding r = GetType(fs); fs.Close(); return r; } /// 經過給定的文件流，判斷文件的編碼類型 /// <param name="fs">文件流</param>
/// <returns>文件的編碼類型</returns>
public static System.Text.Encoding GetType(System.IO.FileStream fs) { byte[] Unicode = new byte[] { 0xFF, 0xFE, 0x41 }; byte[] UnicodeBIG = new byte[] { 0xFE, 0xFF, 0x00 }; byte[] UTF8 = new byte[] { 0xEF, 0xBB, 0xBF }; //帶BOM
    System.Text.Encoding reVal = System.Text.Encoding.Default; System.IO.BinaryReader r = new System.IO.BinaryReader(fs, System.Text.Encoding.Default); int i; int.TryParse(fs.Length.ToString(), out i); byte[] ss = r.ReadBytes(i); if (IsUTF8Bytes(ss) || (ss[0] == 0xEF && ss[1] == 0xBB && ss[2] == 0xBF)) { reVal = System.Text.Encoding.UTF8; } else if (ss[0] == 0xFE && ss[1] == 0xFF && ss[2] == 0x00) { reVal = System.Text.Encoding.BigEndianUnicode; } else if (ss[0] == 0xFF && ss[1] == 0xFE && ss[2] == 0x41) { reVal = System.Text.Encoding.Unicode; } r.Close(); return reVal; } /// 判斷是不是不帶 BOM 的 UTF8 格式 /// <param name="data"></param>
/// <returns></returns>
private static bool IsUTF8Bytes(byte[] data) { int charByteCounter = 1;　 //計算當前正分析的字符應還有的字節數
    byte curByte; //當前分析的字節.
    for (int i = 0; i < data.Length; i++) { curByte = data[i]; if (charByteCounter == 1) { if (curByte >= 0x80) { //判斷當前
                while (((curByte <<= 1) & 0x80) != 0) { charByteCounter++; } //標記位首位若爲非0 則至少以2個1開始 如:110XXXXX...........1111110X　
                if (charByteCounter == 1 || charByteCounter > 6) { return false; } } } else { //如果UTF-8 此時第一位必須爲1
            if ((curByte & 0xC0) != 0x80) { return false; } charByteCounter--; } } if (charByteCounter > 1) { throw new Exception("非預期的byte格式"); } return true; }