NPOI导出Excel (C#) 踩坑 之--The maximum column width for an individual cell is 255 charaters
1 /******************************************************************* 2 * 版权所有： 3 * 类 名 称：ExcelHelper 4 * 作 者：zk 5 * 电子邮箱： 6 * 创建日期：2012/2/25 10:17:21 7 * 修改描述：从excel导入datatable时，可以导入日期类型。 8 * 但对excel中的日期类型有一定要求，要求至少是yyyy/mm/dd类型日期； * 9 * 修改描述：将datatable导入excel中，对类型为字符串的数字进行处理， 10 * 导出数字为double类型； 11 * 12 * 13 * *******************************************************************/ 14 using System; 15 using System.Collections.Generic; 16 using System.Data; 17 using System.IO; 18 using System.Text; 19 using System.Web; 20 using NPOI; 21 using NPOI.HPSF; 22 using NPOI.HSSF; 23 using NPOI.HSSF.Record.Formula.Eval; 24 using NPOI.HSSF.UserModel; 25 using NPOI.HSSF.Util; 26 using NPOI.POIFS; 27 using NPOI.SS.UserModel; 28 using NPOI.Util; 29 using NPOI.SS; 30 using NPOI.DDF; 31 using NPOI.SS.Util; 32 using System.Collections; 33 using System.Text.RegularExpressions; 34 35 namespace chuzhang 36 { 37 public static class ExcelHelper 38 { 39 //private static WriteLog wl = new WriteLog();a 40 41 42 #region 从datatable中将数据导出到excel 43 /// <summary> 44 /// DataTable导出到Excel的MemoryStream 45 /// </summary> 46 /// <param name="dtSource">源DataTable</param> 47 /// <param name="strHeaderText">表头文本</param> 48 public static MemoryStream ExportDT(DataTable dtSource, string strHeaderText) 49 { 50 HSSFWorkbook workbook = new HSSFWorkbook(); 51 HSSFSheet sheet = workbook.CreateSheet() as HSSFSheet; 52 53 #region 右击文件 属性信息 54 55 //{ 56 // DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation(); 57 // dsi.Company = "http://www.yongfa365.com/"; 58 // workbook.DocumentSummaryInformation = dsi; 59 60 // SummaryInformation si = PropertySetFactory.CreateSummaryInformation(); 61 // si.Author = "柳永法"; //填加xls文件作者信息 62 // si.ApplicationName = "NPOI测试程序"; //填加xls文件创建程序信息 63 // si.LastAuthor = "柳永法2"; //填加xls文件最后保存者信息 64 // si.Comments = "说明信息"; //填加xls文件作者信息 65 // si.Title = "NPOI测试"; //填加xls文件标题信息 66 // si.Subject = "NPOI测试Demo"; //填加文件主题信息 67 // si.CreateDateTime = DateTime.Now; 68 // workbook.SummaryInformation = si; 69 //} 70 71 #endregion 72 73 HSSFCellStyle dateStyle = workbook.CreateCellStyle() as HSSFCellStyle; 74 HSSFDataFormat format = workbook.CreateDataFormat() as HSSFDataFormat; 75 dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd"); 76 77 //取得列宽 78 int[] arrColWidth = new int[dtSource.Columns.Count]; 79 foreach (DataColumn item in dtSource.Columns) 80 { 81 arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length; 82 } 83 for (int i = 0; i < dtSource.Rows.Count; i++) 84 { 85 for (int j = 0; j < dtSource.Columns.Count; j++) 86 { 87 int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][j].ToString()).Length; 88 if (intTemp > arrColWidth[j]) 89 { 90 arrColWidth[j] = intTemp; 91 } 92 } 93 } 94 int rowIndex = 0; 95 96 foreach (DataRow row in dtSource.Rows) 97 { 98 #region 新建表，填充表头，填充列头，样式 99 100 if (rowIndex == 65535 || rowIndex == 0) 101 { 102 if (rowIndex != 0) 103 { 104 sheet = workbook.CreateSheet() as HSSFSheet; 105 } 106 107 #region 表头及样式 108 109 { 110 HSSFRow headerRow = sheet.CreateRow(0) as HSSFRow; 111 headerRow.HeightInPoints = 25; 112 headerRow.CreateCell(0).SetCellValue(strHeaderText); 113 114 HSSFCellStyle headStyle = workbook.CreateCellStyle() as HSSFCellStyle; 115 headStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.CENTER; 116 HSSFFont font = workbook.CreateFont() as HSSFFont; 117 font.FontHeightInPoints = 20; 118 font.Boldweight = 700; 119 headStyle.SetFont(font); 120 121 headerRow.GetCell(0).CellStyle = headStyle; 122 123 sheet.AddMergedRegion(new Region(0, 0, 0, dtSource.Columns.Count - 1)); 124 //headerRow.Dispose(); 125 } 126 127 #endregion 128 129 130 #region 列头及样式 131 132 { 133 HSSFRow headerRow = sheet.CreateRow(1) as HSSFRow; 134 135 136 HSSFCellStyle headStyle = workbook.CreateCellStyle() as HSSFCellStyle; 137 headStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.CENTER; 138 HSSFFont font = workbook.CreateFont() as HSSFFont; 139 font.FontHeightInPoints = 10; 140 font.Boldweight = 700; 141 headStyle.SetFont(font); 142 143 144 foreach (DataColumn column in dtSource.Columns) 145 { 146 headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName); 147 headerRow.GetCell(column.Ordinal).CellStyle = headStyle; 148 149 //设置列宽 150 sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1)*256); 151 152 } 153 //headerRow.Dispose(); 154 } 155 156 #endregion 157 158 rowIndex = 2; 159 } 160 161 #endregion 162 163 #region 填充内容 164 165 HSSFRow dataRow = sheet.CreateRow(rowIndex) as HSSFRow; 166 foreach (DataColumn column in dtSource.Columns) 167 { 168 HSSFCell newCell = dataRow.CreateCell(column.Ordinal) as HSSFCell; 169 170 string drValue = row[column].ToString(); 171 172 switch (column.DataType.ToString()) 173 { 174 case "System.String": //字符串类型 175 double result; 176 if(isNumeric(drValue,out result)) 177 { 178 179 double.TryParse(drValue, out result); 180 newCell.SetCellValue(result); 181 break; 182 } 183 else 184 { 185 newCell.SetCellValue(drValue); 186 break; 187 } 188 189 case "System.DateTime": //日期类型 190 DateTime dateV; 191 DateTime.TryParse(drValue, out dateV); 192 newCell.SetCellValue(dateV); 193 194 newCell.CellStyle = dateStyle; //格式化显示 195 break; 196 case "System.Boolean": //布尔型 197 bool boolV = false; 198 bool.TryParse(drValue, out boolV); 199 newCell.SetCellValue(boolV); 200 break; 201 case "System.Int16": //整型 202 case "System.Int32": 203 case "System.Int64": 204 case "System.Byte": 205 int intV = 0; 206 int.TryParse(drValue, out intV); 207 newCell.SetCellValue(intV); 208 break; 209 case "System.Decimal": //浮点型 210 case "System.Double": 211 double doubV = 0; 212 double.TryParse(drValue, out doubV); 213 newCell.SetCellValue(doubV); 214 break; 215 case "System.DBNull": //空值处理 216 newCell.SetCellValue(""); 217 break; 218 default: 219 newCell.SetCellValue(""); 220 break; 221 } 222 223 } 224 225 #endregion 226 227 rowIndex++; 228 } 229 using (MemoryStream ms = new MemoryStream()) 230 { 231 workbook.Write(ms); 232 ms.Flush(); 233 ms.Position = 0; 234 235 sheet.Dispose(); 236 workbook.Dispose(); 237 238 return ms; 239 } 240 } 241 242 /// <summary> 243 /// DataTable导出到Excel文件 244 /// </summary> 245 /// <param name="dtSource">源DataTable</param> 246 /// <param name="strHeaderText">表头文本</param> 247 /// <param name="strFileName">保存位置</param> 248 public static void ExportDTtoExcel(DataTable dtSource, string strHeaderText, string strFileName) 249 { 250 using (MemoryStream ms = ExportDT(dtSource, strHeaderText)) 251 { 252 using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write)) 253 { 254 byte[] data = ms.ToArray(); 255 fs.Write(data, 0, data.Length); 256 fs.Flush(); 257 } 258 } 259 } 260 #endregion 261 262 #region 从excel中将数据导出到datatable 263 /// <summary>读取excel 264 /// 默认第一行为标头 265 /// </summary> 266 /// <param name="strFileName">excel文档路径</param> 267 /// <returns></returns> 268 public static DataTable ImportExceltoDt(string strFileName) 269 { 270 DataTable dt = new DataTable(); 271 HSSFWorkbook hssfworkbook; 272 using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read)) 273 { 274 hssfworkbook = new HSSFWorkbook(file); 275 } 276 HSSFSheet sheet = hssfworkbook.GetSheetAt(0) as HSSFSheet; 277 dt = ImportDt(sheet, 0, true); 278 return dt; 279 } 280 281 /// <summary> 282 /// 读取excel 283 /// </summary> 284 /// <param name="strFileName">excel文件路径</param> 285 /// <param name="sheet">需要导出的sheet</param> 286 /// <param name="HeaderRowIndex">列头所在行号，-1表示没有列头</param> 287 /// <returns></returns> 288 public static DataTable ImportExceltoDt(string strFileName, string SheetName, int HeaderRowIndex) 289 { 290 HSSFWorkbook workbook; 291 using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read)) 292 { 293 workbook = new HSSFWorkbook(file); 294 } 295 HSSFSheet sheet = workbook.GetSheet(SheetName) as HSSFSheet; 296 DataTable table = new DataTable(); 297 table = ImportDt(sheet, HeaderRowIndex, true); 298 //ExcelFileStream.Close(); 299 workbook = null; 300 sheet = null; 301 return table; 302 } 303 304 /// <summary> 305 /// 读取excel 306 /// </summary> 307 /// <param name="strFileName">excel文件路径</param> 308 /// <param name="sheet">需要导出的sheet序号</param> 309 /// <param name="HeaderRowIndex">列头所在行号，-1表示没有列头</param> 310 /// <returns></returns> 311 public static DataTable ImportExceltoDt(string strFileName, int SheetIndex, int HeaderRowIndex) 312 { 313 HSSFWorkbook workbook; 314 using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read)) 315 { 316 workbook = new HSSFWorkbook(file); 317 } 318 HSSFSheet sheet = workbook.GetSheetAt(SheetIndex) as HSSFSheet; 319 DataTable table = new DataTable(); 320 table = ImportDt(sheet, HeaderRowIndex, true); 321 //ExcelFileStream.Close(); 322 workbook = null; 323 sheet = null; 324 return table; 325 } 326 327 /// <summary> 328 /// 读取excel 329 /// </summary> 330 /// <param name="strFileName">excel文件路径</param> 331 /// <param name="sheet">需要导出的sheet</param> 332 /// <param name="HeaderRowIndex">列头所在行号，-1表示没有列头</param> 333 /// <returns></returns> 334 public static DataTable ImportExceltoDt(string strFileName, string SheetName, int HeaderRowIndex, bool needHeader) 335 { 336 HSSFWorkbook workbook; 337 using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read)) 338 { 339 workbook = new HSSFWorkbook(file); 340 } 341 HSSFSheet sheet = workbook.GetSheet(SheetName) as HSSFSheet; 342 DataTable table = new DataTable(); 343 table = ImportDt(sheet, HeaderRowIndex, needHeader); 344 //ExcelFileStream.Close(); 345 workbook = null; 346 sheet = null; 347 return table; 348 } 349 350 /// <summary> 351 /// 读取excel 352 /// </summary> 353 /// <param name="strFileName">excel文件路径</param> 354 /// <param name="sheet">需要导出的sheet序号</param> 355 /// <param name="HeaderRowIndex">列头所在行号，-1表示没有列头</param> 356 /// <returns></returns> 357 public static DataTable ImportExceltoDt(string strFileName, int SheetIndex, int HeaderRowIndex, bool needHeader) 358 { 359 HSSFWorkbook workbook; 360 using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read)) 361 { 362 workbook = new HSSFWorkbook(file); 363 } 364 HSSFSheet sheet = workbook.GetSheetAt(SheetIndex) as HSSFSheet; 365 DataTable table = new DataTable(); 366 table = ImportDt(sheet, HeaderRowIndex, needHeader); 367 //ExcelFileStream.Close(); 368 workbook = null; 369 sheet = null; 370 return table; 371 } 372 373 /// <summary> 374 /// 将制定sheet中的数据导出到datatable中 375 /// </summary> 376 /// <param name="sheet">需要导出的sheet</param> 377 /// <param name="HeaderRowIndex">列头所在行号，-1表示没有列头</param> 378 /// <returns></returns> 379 static DataTable ImportDt(HSSFSheet sheet, int HeaderRowIndex,bool needHeader) 380 { 381 DataTable table = new DataTable(); 382 HSSFRow headerRow; 383 int cellCount; 384 try 385 { 386 if (HeaderRowIndex < 0 || !needHeader) 387 { 388 headerRow = sheet.GetRow(0) as HSSFRow; 389 cellCount = headerRow.LastCellNum; 390 391 for (int i = headerRow.FirstCellNum; i <= cellCount; i++) 392 { 393 DataColumn column = new DataColumn(Convert.ToString(i)); 394 table.Columns.Add(column); 395 } 396 } 397 else 398 { 399 headerRow = sheet.GetRow(HeaderRowIndex) as HSSFRow; 400 cellCount = headerRow.LastCellNum; 401 402 for (int i = headerRow.FirstCellNum; i <= cellCount; i++) 403 { 404 if (headerRow.GetCell(i) == null) 405 { 406 if(table.Columns.IndexOf(Convert.ToString(i)) > 0) 407 { 408 DataColumn column = new DataColumn(Convert.ToString("重复列名" + i)); 409 table.Columns.Add(column); 410 } 411 else 412 { 413 DataColumn column = new DataColumn(Convert.ToString(i)); 414 table.Columns.Add(column); 415 } 416 417 } 418 else if (table.Columns.IndexOf(headerRow.GetCell(i).ToString()) > 0) 419 { 420 DataColumn column = new DataColumn(Convert.ToString("重复列名" + i)); 421 table.Columns.Add(column); 422 } 423 else 424 { 425 DataColumn column = new DataColumn(headerRow.GetCell(i).ToString()); 426 table.Columns.Add(column); 427 } 428 } 429 } 430 int rowCount = sheet.LastRowNum; 431 for (int i = (HeaderRowIndex + 1); i <= sheet.LastRowNum; i++) 432 { 433 try 434 { 435 HSSFRow row; 436 if (sheet.GetRow(i) == null) 437 { 438 row = sheet.CreateRow(i) as HSSFRow; 439 } 440 else 441 { 442 row = sheet.GetRow(i) as HSSFRow; 443 } 444 445 DataRow dataRow = table.NewRow(); 446 447 for (int j = row.FirstCellNum; j <= cellCount; j++) 448 { 449 try 450 { 451 if (row.GetCell(j) != null) 452 { 453 switch (row.GetCell(j).CellType) 454 { 455 case CellType.STRING: 456 string str = row.GetCell(j).StringCellValue; 457 if (str != null && str.Length > 0) 458 { 459 dataRow[j] = str.ToString(); 460 } 461 else 462 { 463 dataRow[j] = null; 464 } 465 break; 466 case CellType.NUMERIC: 467 if (DateUtil.IsCellDateFormatted(row.GetCell(j))) 468 { 469 dataRow[j] = DateTime.FromOADate(row.GetCell(j).NumericCellValue); 470 } 471 else 472 { 473 dataRow[j] = Convert.ToDouble(row.GetCell(j).NumericCellValue); 474 } 475 break; 476 case CellType.BOOLEAN: 477 dataRow[j] = Convert.ToString(row.GetCell(j).BooleanCellValue); 478 break; 479 case CellType.ERROR: 480 dataRow[j] = ErrorEval.GetText(row.GetCell(j).ErrorCellValue); 481 break; 482 case CellType.FORMULA: 483 switch (row.GetCell(j).CachedFormulaResultType) 484 { 485 case CellType.STRING: 486 string strFORMULA = row.GetCell(j).StringCellValue; 487 if (strFORMULA != null && strFORMULA.Length > 0) 488 { 489 dataRow[j] = strFORMULA.ToString(); 490 } 491 else 492 { 493 dataRow[j] = null; 494 } 495 break; 496 case CellType.NUMERIC: 497 dataRow[j] = Convert.ToString(row.GetCell(j).NumericCellValue); 498 break; 499 case CellType.BOOLEAN: 500 dataRow[j] = Convert.ToString(row.GetCell(j).BooleanCellValue); 501 break; 502 case CellType.ERROR: 503 dataRow[j] = ErrorEval.GetText(row.GetCell(j).ErrorCellValue); 504 break; 505 default: 506 dataRow[j] = ""; 507 break; 508 } 509 break; 510 default: 511 dataRow[j] = ""; 512 break; 513 } 514 } 515 } 516 catch (Exception exception) 517 { 518 //wl.WriteLogs(exception.ToString()); 519 } 520 } 521 table.Rows.Add(dataRow); 522 } 523 catch (Exception exception) 524 { 525 //wl.WriteLogs(exception.ToString()); 526 } 527 } 528 } 529 catch (Exception exception) 530 { 531 //wl.WriteLogs(exception.ToString()); 532 } 533 return table; 534 } 535 #endregion 536 537 #region 更新excel中的数据 538 /// <summary> 539 /// 更新Excel表格 540 /// </summary> 541 /// <param name="outputFile">需更新的excel表格路径</param> 542 /// <param name="sheetname">sheet名</param> 543 /// <param name="updateData">需更新的数据</param> 544 /// <param name="coluid">需更新的列号</param> 545 /// <param name="rowid">需更新的开始行号</param> 546 public static void UpdateExcel(string outputFile, string sheetname, string[] updateData, int coluid, int rowid) 547 { 548 FileStream readfile = new FileStream(outputFile, FileMode.Open, FileAccess.Read); 549 550 HSSFWorkbook hssfworkbook = new HSSFWorkbook(readfile); 551 ISheet sheet1 = hssfworkbook.GetSheet(sheetname); 552 for (int i = 0; i < updateData.Length; i++) 553 { 554 try 555 { 556 if(sheet1.GetRow(i+rowid) == null) 557 { 558 sheet1.CreateRow(i + rowid); 559 } 560 if (sheet1.GetRow(i + rowid).GetCell(coluid) == null) 561 { 562 sheet1.GetRow(i + rowid).CreateCell(coluid); 563 } 564 565 sheet1.GetRow(i + rowid).GetCell(coluid).SetCellValue(updateData[i]); 566 } 567 catch (Exception ex) 568 { 569 // wl.WriteLogs(ex.ToString()); 570 throw; 571 } 572 } 573 try 574 { 575 readfile.Close(); 576 FileStream writefile = new FileStream(outputFile, FileMode.Create,FileAccess.Write); 577 hssfworkbook.Write(writefile); 578 writefile.Close(); 579 } 580 catch (Exception ex) 581 { 582 // wl.WriteLogs(ex.ToString()); 583 } 584 585 } 586 587 /// <summary> 588 /// 更新Excel表格 589 /// </summary> 590 /// <param name="outputFile">需更新的excel表格路径</param> 591 /// <param name="sheetname">sheet名</param> 592 /// <param name="updateData">需更新的数据</param> 593 /// <param name="coluids">需更新的列号</param> 594 /// <param name="rowid">需更新的开始行号</param> 595 public static void UpdateExcel(string outputFile, string sheetname, string[][] updateData, int [] coluids, int rowid) 596 { 597 FileStream readfile = new FileStream(outputFile, FileMode.Open, FileAccess.Read); 598 599 HSSFWorkbook hssfworkbook = new HSSFWorkbook(readfile); 600 readfile.Close(); 601 ISheet sheet1 = hssfworkbook.GetSheet(sheetname); 602 for (int j = 0; j < coluids.Length; j++) 603 { 604 for (int i = 0; i < updateData[j].Length; i++) 605 { 606 try 607 { 608 if (sheet1.GetRow(i + rowid) == null) 609 { 610 sheet1.CreateRow(i + rowid); 611 } 612 if (sheet1.GetRow(i + rowid).GetCell(coluids[j]) == null) 613 { 614 sheet1.GetRow(i + rowid).CreateCell(coluids[j]); 615 } 616 sheet1.GetRow(i + rowid).GetCell(coluids[j]).SetCellValue(updateData[j][i]); 617 } 618 catch (Exception ex) 619 { 620 // wl.WriteLogs(ex.ToString()); 621 } 622 } 623 } 624 try 625 { 626 FileStream writefile = new FileStream(outputFile, FileMode.Create); 627 hssfworkbook.Write(writefile); 628 writefile.Close(); 629 } 630 catch (Exception ex) 631 { 632 //wl.WriteLogs(ex.ToString()); 633 } 634 } 635 636 /// <summary> 637 /// 更新Excel表格 638 /// </summary> 639 /// <param name="outputFile">需更新的excel表格路径</param> 640 /// <param name="sheetname">sheet名</param> 641 /// <param name="updateData">需更新的数据</param> 642 /// <param name="coluid">需更新的列号</param> 643 /// <param name="rowid">需更新的开始行号</param> 644 public static void UpdateExcel(string outputFile, string sheetname, double [] updateData, int coluid, int rowid) 645 { 646 FileStream readfile = new FileStream(outputFile, FileMode.Open, FileAccess.Read); 647 648 HSSFWorkbook hssfworkbook = new HSSFWorkbook(readfile); 649 ISheet sheet1 = hssfworkbook.GetSheet(sheetname); 650 for (int i = 0; i < updateData.Length; i++) 651 { 652 try 653 { 654 if (sheet1.GetRow(i + rowid) == null) 655 { 656 sheet1.CreateRow(i + rowid); 657 } 658 if (sheet1.GetRow(i + rowid).GetCell(coluid) == null) 659 { 660 sheet1.GetRow(i + rowid).CreateCell(coluid); 661 } 662 663 sheet1.GetRow(i + rowid).GetCell(coluid).SetCellValue(updateData[i]); 664 } 665 catch (Exception ex) 666 { 667 //wl.WriteLogs(ex.ToString()); 668 throw; 669 } 670 } 671 try 672 { 673 readfile.Close(); 674 FileStream writefile = new FileStream(outputFile, FileMode.Create, FileAccess.Write); 675 hssfworkbook.Write(writefile); 676 writefile.Close(); 677 } 678 catch (Exception ex) 679 { 680 //wl.WriteLogs(ex.ToString()); 681 } 682 683 } 684 685 /// <summary> 686 /// 更新Excel表格 687 /// </summary> 688 /// <param name="outputFile">需更新的excel表格路径</param> 689 /// <param name="sheetname">sheet名</param> 690 /// <param name="updateData">需更新的数据</param> 691 /// <param name="coluids">需更新的列号</param> 692 /// <param name="rowid">需更新的开始行号</param> 693 public static void UpdateExcel(string outputFile, string sheetname, double[][] updateData, int[] coluids, int rowid) 694 { 695 FileStream readfile = new FileStream(outputFile, FileMode.Open, FileAccess.Read); 696 697 HSSFWorkbook hssfworkbook = new HSSFWorkbook(readfile); 698 readfile.Close(); 699 ISheet sheet1 = hssfworkbook.GetSheet(sheetname); 700 for (int j = 0; j < coluids.Length; j++) 701 { 702 for (int i = 0; i < updateData[j].Length; i++) 703 { 704 try 705 { 706 if (sheet1.GetRow(i + rowid) == null) 707 { 708 sheet1.CreateRow(i + rowid); 709 } 710 if (sheet1.GetRow(i + rowid).GetCell(coluids[j]) == null) 711 { 712 sheet1.GetRow(i + rowid).CreateCell(coluids[j]); 713 } 714 sheet1.GetRow(i + rowid).GetCell(coluids[j]).SetCellValue(updateData[j][i]); 715 } 716 catch (Exception ex) 717 { 718 //wl.WriteLogs(ex.ToString()); 719 } 720 } 721 } 722 try 723 { 724 FileStream writefile = new FileStream(outputFile, FileMode.Create); 725 hssfworkbook.Write(writefile); 726 writefile.Close(); 727 } 728 catch (Exception ex) 729 { 730 //wl.WriteLogs(ex.ToString()); 731 } 732 } 733 734 #endregion 735 736 public static int GetSheetNumber(string outputFile) 737 { 738 int number = 0; 739 try 740 { 741 FileStream readfile = new FileStream(outputFile, FileMode.Open, FileAccess.Read); 742 743 HSSFWorkbook hssfworkbook = new HSSFWorkbook(readfile); 744 number = hssfworkbook.NumberOfSheets; 745 746 } 747 catch (Exception exception) 748 { 749 //wl.WriteLogs(exception.ToString()); 750 } 751 return number; 752 } 753 754 public static ArrayList GetSheetName(string outputFile) 755 { 756 ArrayList arrayList = new ArrayList(); 757 try 758 { 759 FileStream readfile = new FileStream(outputFile, FileMode.Open, FileAccess.Read); 760 761 HSSFWorkbook hssfworkbook = new HSSFWorkbook(readfile); 762 for(int i = 0 ;i<hssfworkbook.NumberOfSheets;i++) 763 { 764 arrayList.Add(hssfworkbook.GetSheetName(i)); 765 } 766 } 767 catch (Exception exception) 768 { 769 //wl.WriteLogs(exception.ToString()); 770 } 771 return arrayList; 772 } 773 774 public static bool isNumeric(String message, out double result) 775 { 776 Regex rex =new Regex(@"^[-]?d+[.]?d*$"); 777 result = -1; 778 if (rex.IsMatch(message)) 779 { 780 result = double.Parse(message); 781 return true; 782 } 783 else 784 return false; 785 786 } 787 } 788 }
声明：上面的类是我在网上找来的，功能和写法与下文相似，所以不要对号入座！！！！
公司的高大上的程序员建立代码库，其中有一个功能就是用NPOI导出Excel功能（参考以上的类代码），今天突然有个用户说到他查询出来的数据导出Excel有报错！
调试一番，捕捉到以下错误：
我晕了，高大上的程序员建立的代码库怎么会有错呢？×叉 ×！！完全颠覆我的人生观！！于是问回其作者，得到的答复：”怎么会有错呢？一定是你代码的问题！“
心里犹如万匹草泥马.......很有礼貌地问候了他后，还是一步一步找问题;
经过一番度娘，Stackoverflow后，已经本人亲自操作后发现Excel的列宽
所以导出Excel时列宽超过了255后，就会报错了。
所以应该在Excel列宽上加一层判断：
//设置列宽
if (arrColWidth[column.Ordinal]>255)
{
arrColWidth[column.Ordinal] = 254;
}
else
{
sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);
}
总结：为免踩坑，以后引用高大上的类库，也要有怀疑的精神！哎！！