将DataTable转换为CSV的最有效方法

我正在使用DataTable，我需要将它们转换为CSV文件格式。 我正在使用的大多数表都有超过50,000条记录，因此我试图最小化转换它们所需的时间。

这是我目前的方法：

public static string table_to_csv(DataTable table) { string file = ""; foreach (DataColumn col in table.Columns) file = string.Concat(file, col.ColumnName, ","); file = file.Remove(file.LastIndexOf(','), 1); file = string.Concat(file, "\r\n"); foreach (DataRow row in table.Rows) { foreach (object item in row.ItemArray) file = string.Concat(file, item.ToString(), ","); file = file.Remove(file.LastIndexOf(','), 1); file = string.Concat(file, "\r\n"); } return file; } 

有什么办法可以提高这种方法的效率吗？ 我欢迎您提出任何修改和想法！

Answer 1

是的，使用System.Text.StringBuilder来表示巨大的字符串。 我实现了这个：

 public static string DataTableToCSV(this DataTable datatable, char seperator) { StringBuilder sb = new StringBuilder(); for (int i = 0; i < datatable.Columns.Count; i++) { sb.Append(datatable.Columns[i]); if (i < datatable.Columns.Count - 1) sb.Append(seperator); } sb.AppendLine(); foreach (DataRow dr in datatable.Rows) { for (int i = 0; i < datatable.Columns.Count; i++) { sb.Append(dr[i].ToString()); if (i < datatable.Columns.Count - 1) sb.Append(seperator); } sb.AppendLine(); } return sb.ToString(); } 

Answer 2

这是我在Utility类中使用的方法。 适合我正在做的事情。

  public static void GenerateCSV(DataTable dt) { StringBuilder sb = new StringBuilder(); try { int count = 1; int totalColumns = dt.Columns.Count; foreach (DataColumn dr in dt.Columns) { sb.Append(dr.ColumnName); if (count != totalColumns) { sb.Append(","); } count++; } sb.AppendLine(); string value = String.Empty; foreach (DataRow dr in dt.Rows) { for (int x = 0; x < totalColumns; x++) { value = dr[x].ToString(); if (value.Contains(",") || value.Contains("\"")) { value = '"' + value.Replace("\"", "\"\"") + '"'; } sb.Append(value); if (x != (totalColumns - 1)) { sb.Append(","); } } sb.AppendLine(); } } catch (Exception ex) { // Do something } } 

Answer 3

我已经使用这种方法将对象数组复制到Excel单元格范围而不是逐行复制然后逐列复制它被certificate是非常有效的方式

  public void ExportToExcel(DataTable dataTable, String pathToSave) { // Create the Excel Application object var excelApp = new ApplicationClass(); // Create a new Excel Workbook Workbook excelWorkbook = excelApp.Workbooks.Add(Type.Missing); int sheetIndex = 0; // Copy the DataTable to an object array var rawData = new object[dataTable.Rows.Count + 1, dataTable.Columns.Count]; // Copy the column names to the first row of the object array for (var col = 0; col < dataTable.Columns.Count; col++) { rawData[0, col] = dataTable.Columns[col].ColumnName; } // Copy the values to the object array for (var col = 0; col < dataTable.Columns.Count; col++) { for (int row = 0; row < dataTable.Rows.Count; row++) { rawData[row + 1, col] = dataTable.Rows[row].ItemArray[col]; } } // Calculate the final column letter string finalColLetter = string.Empty; const string colCharset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; int colCharsetLen = colCharset.Length; if (dataTable.Columns.Count > colCharsetLen) { finalColLetter = colCharset.Substring( (dataTable.Columns.Count - 1) / colCharsetLen - 1, 1); } finalColLetter += colCharset.Substring((dataTable.Columns.Count - 1) % colCharsetLen, 1); // Create a new Sheet var excelSheet = (Worksheet)excelWorkbook.Sheets.Add(excelWorkbook.Sheets.Item[++sheetIndex], Type.Missing, 1, XlSheetType.xlWorksheet); excelSheet.Name = dataTable.TableName; // Fast data export to Excel var excelRange = string.Format("A1:{0}{1}", finalColLetter, dataTable.Rows.Count + 1); excelSheet.Range[excelRange, Type.Missing].Value2 = rawData; // Mark the first row as BOLD and BLUE var headerColumnRange = (Range)excelSheet.Rows[1, Type.Missing]; headerColumnRange.Font.Bold = true; headerColumnRange.Font.Color = 0xFF0000; headerColumnRange.EntireColumn.AutoFit(); // Save and Close the Workbook excelWorkbook.SaveAs(pathToSave, XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, Type.Missing, Type.Missing, XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); excelWorkbook.Close(true, Type.Missing, Type.Missing); excelWorkbook = null; // Release the Application object excelApp.Quit(); excelApp = null; // Collect the unreferenced objects GC.Collect(); GC.WaitForPendingFinalizers(); }