NPOI作為開源免費的組件，功能強大，可用來讀寫Excel(兼容xls和xlsx兩種版本)、Word、PPT文件。可是要讓我們記住所有的操作，這便有點困難了，至此，總結一些在開發中常用的針對Excel的簡單。NPOI官網地址
本文地址：https://www.cnblogs.com/CKExp/p/9626022.html
一、NPOI的安裝
下載NPOI或是通過Nuget包加入進來，然后在代碼中引用如下命名空間，然后開始讀寫Excel文件。
using NPOI.SS.UserModel; using NPOI.XSSF.UserModel; using NPOI.HSSF.UserModel; using NPOI.SS.Util;
二、NPOI寫入Excel文件
在NPOI中，使用HSSFWorkbook類類來處理xls結尾的Excel文件(版本在2003及以前)，XSSFWorkbook類來處理xlsx結尾的Excel文件(版本在2007及以后)，都繼承自接口IWorkbook，我們可以使用IWorkbook來統一處理兩種不同格式的Excel文件。
直接參考相關代碼即可，對於合並單元格的跨行跨列操作，無需將被跨掉的行生成新行，合並單元格的信息是單獨保存的。設置單元格樣式時，請創建一個新的樣式對象，不創建將使用默認的樣式對象。
1 /// <summary> 2 /// Datable導出到Excel 3 /// </summary> 4 /// <returns></returns> 5 public static void DataTableToExcel() 6 { 7 //一些已有數據信息 8 bool fileSaved = false; 9 SaveFileDialog saveDialog = new SaveFileDialog 10 { 11 DefaultExt = "xls", 12 Filter = "Excel文件|*.xls", 13 FileName = DateTime.Now.ToString("yyyyMMdd") + "-" + enterpriseTable.Rows[0]["名稱"].ToString() + "委托書" 14 }; 15 saveDialog.ShowDialog(); 16 string saveFileName = saveDialog.FileName; 17 if (saveFileName.IndexOf(":") < 0) return; //被點了取消 18 if (saveFileName != "") 19 { 20 try 21 { 22 IWorkbook workbook; 23 string fileExt = System.IO.Path.GetExtension(saveFileName).ToLower(); 24 if (fileExt == ".xlsx") 25 { 26 workbook = new XSSFWorkbook(); 27 } 28 else if (fileExt == ".xls") 29 { 30 workbook = new HSSFWorkbook(); 31 } 32 else 33 { 34 return; 35 } 36 37 ISheet sheet = workbook.CreateSheet("Sheet1"); 38 39 sheet.AddMergedRegion(new CellRangeAddress(0, 3, 0, 9));//合並單元格 40 IRow row = sheet.CreateRow(0);//創建首行 41 ICell cell = row.CreateCell(0);//行中創建第一列 42 cell.SetCellValue("標題"); 43 ICellStyle style = workbook.CreateCellStyle();//設置樣式，創建新的style實例，脫離統一樣式 44 style.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;//設置單元格的樣式：水平對齊居中 45 style.VerticalAlignment = NPOI.SS.UserModel.VerticalAlignment.Center; 46 47 IFont font = workbook.CreateFont();//新建一個字體樣式對象 48 font.Boldweight = short.MaxValue; //設置字體加粗樣式 49 style.SetFont(font); //使用SetFont方法將字體樣式添加到單元格樣式中 50 cell.CellStyle = style; //將新的樣式賦給單元格 51 52 sheet.AddMergedRegion(new CellRangeAddress(4, 4, 1, 4)); 53 sheet.AddMergedRegion(new CellRangeAddress(4, 4, 6, 9)); 54 row = sheet.CreateRow(4); 55 cell = row.CreateCell(0); 56 cell.SetCellValue("編號:"); 57 cell = row.CreateCell(1); 58 cell.SetCellValue(planCode); 59 cell = row.CreateCell(5); 60 cell.SetCellValue("日期："); 61 cell = row.CreateCell(6); 62 cell.SetCellValue(taskPlantable.Rows[0]["編制日期"].ToString()); 63 64 sheet.AddMergedRegion(new CellRangeAddress(5, 5, 1, 4)); 65 sheet.AddMergedRegion(new CellRangeAddress(5, 5, 6, 9)); 66 row = sheet.CreateRow(5); 67 cell = row.CreateCell(0); 68 cell.SetCellValue("單位:"); 69 cell = row.CreateCell(1); 70 cell.SetCellValue(enterpriseTable.Rows[0]["名稱"].ToString()); 71 cell = row.CreateCell(5); 72 cell.SetCellValue("聯系人："); 73 cell = row.CreateCell(6); 74 cell.SetCellValue(enterpriseTable.Rows[0]["聯系人"].ToString()); 75 76 sheet.AddMergedRegion(new CellRangeAddress(6, 6, 1, 4)); 77 sheet.AddMergedRegion(new CellRangeAddress(6, 6, 6, 9)); 78 row = sheet.CreateRow(6); 79 cell = row.CreateCell(0); 80 cell.SetCellValue("傳真:"); 81 cell = row.CreateCell(1); 82 cell.SetCellValue(enterpriseTable.Rows[0]["傳真"].ToString()); 83 cell = row.CreateCell(5); 84 cell.SetCellValue("聯系電話："); 85 cell = row.CreateCell(6); 86 cell.SetCellValue(enterpriseTable.Rows[0]["電話"].ToString()); 87 88 sheet.AddMergedRegion(new CellRangeAddress(7, 7, 1, 9)); 89 row = sheet.CreateRow(7); 90 cell = row.CreateCell(0); 91 cell.SetCellValue("詳細地址:"); 92 cell = row.CreateCell(1); 93 cell.SetCellValue(enterpriseTable.Rows[0]["詳細地址"].ToString()); 94 95 int index = 7; 96 //數據 97 for (int i = 0; i < taskProjectTable.Rows.Count; i++) 98 { 99 index++; 100 sheet.AddMergedRegion(new CellRangeAddress(index, index, 1, 4)); 101 sheet.AddMergedRegion(new CellRangeAddress(index, index, 6, 9)); 102 row = sheet.CreateRow(index); 103 cell = row.CreateCell(0); 104 cell.SetCellValue("名稱:"); 105 cell = row.CreateCell(1); 106 cell.SetCellValue(taskProjectTable.Rows[i]["名稱"].ToString()); 107 cell = row.CreateCell(5); 108 cell.SetCellValue("類型:"); 109 cell = row.CreateCell(6); 110 cell.SetCellValue(taskProjectTable.Rows[i]["項目類型"].ToString()); 111 112 index++; 113 sheet.AddMergedRegion(new CellRangeAddress(index, index, 0, 2)); 114 sheet.AddMergedRegion(new CellRangeAddress(index, index, 3, 5)); 115 sheet.AddMergedRegion(new CellRangeAddress(index, index, 6, 9)); 116 row = sheet.CreateRow(index); 117 cell = row.CreateCell(0); 118 cell.SetCellValue("項目"); 119 cell = row.CreateCell(3); 120 cell.SetCellValue("方法"); 121 cell = row.CreateCell(6); 122 cell.SetCellValue("儀器"); 123 124 //獲取數據信息 125 DataTable taskDataTable = mysql.GetTableFromSQL(selstr.ToString()); 126 selstr.Clear(); 127 for (int j = 0; j < taskDataTable.Rows.Count; j++) 128 { 129 index++; 130 sheet.AddMergedRegion(new CellRangeAddress(index, index, 0, 2)); 131 sheet.AddMergedRegion(new CellRangeAddress(index, index, 3, 5)); 132 sheet.AddMergedRegion(new CellRangeAddress(index, index, 6, 9)); 133 row = sheet.CreateRow(index); 134 cell = row.CreateCell(0); 135 cell.SetCellValue(taskDataTable.Rows[j]["名稱"].ToString()); 136 cell = row.CreateCell(3); 137 cell.SetCellValue(taskDataTable.Rows[j]["方法"].ToString()); 138 cell = row.CreateCell(6); 139 cell.SetCellValue(taskDataTable.Rows[j]["儀器型號"].ToString()); 140 } 141 } 142 143 //轉為字節數組 144 MemoryStream stream = new MemoryStream(); 145 workbook.Write(stream); 146 var buf = stream.ToArray(); 147 148 //保存為Excel文件 149 using (FileStream fs = new FileStream(saveDialog.FileName, FileMode.Create, FileAccess.Write)) 150 { 151 fs.Write(buf, 0, buf.Length); 152 fs.Flush(); 153 } 154 fileSaved = true; 155 } 156 catch (Exception ex) 157 { 158 fileSaved = false; 159 MessageBox.Show("導出文件時出錯,文件可能正被打開！\n" + ex.Message); 160 } 161 } 162 GC.Collect();//強行銷毀 163 164 if (fileSaved && File.Exists(saveFileName)) 165 { 166 MessageBox.Show("導出成功！", "通知"); 167 Process.Start(saveFileName); 168 } 169 else 170 { 171 MessageBox.Show("導出失敗！", "通知"); 172 } 173 }
三、NPOI讀取Excel文件
打開指定Excel文件並讀取文件中的內容，加入到DataTable中，或是加入到其它的數據載體中。
1 /// <summary> 2 /// Excel導入成DataTble 3 /// </summary> 4 /// <param name="file">導入路徑(包含文件名與擴展名)</param> 5 /// <returns></returns> 6 public static DataTable ExcelToTable(string file) 7 { 8 DataTable dt = new DataTable(); 9 IWorkbook workbook; 10 string fileExt = Path.GetExtension(file).ToLower(); 11 using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read)) 12 { 13 if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(fs); } else if (fileExt == ".xls") { workbook = new HSSFWorkbook(fs); } else { workbook = null; } 14 if (workbook == null) { return null; } 15 ISheet sheet = workbook.GetSheetAt(0); 16 17 //表頭 18 IRow header = sheet.GetRow(sheet.FirstRowNum); 19 List<int> columns = new List<int>(); 20 for (int i = 0; i < header.LastCellNum; i++) 21 { 22 object obj = GetValueType(header.GetCell(i)); 23 if (obj == null || obj.ToString() == string.Empty) 24 { 25 dt.Columns.Add(new DataColumn("Columns" + i.ToString())); 26 } 27 else 28 dt.Columns.Add(new DataColumn(obj.ToString())); 29 columns.Add(i); 30 } 31 //數據 32 for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum; i++) 33 { 34 DataRow dr = dt.NewRow(); 35 bool hasValue = false; 36 foreach (int j in columns) 37 { 38 dr[j] = GetValueType(sheet.GetRow(i).GetCell(j)); 39 if (dr[j] != null && dr[j].ToString() != string.Empty) 40 { 41 hasValue = true; 42 } 43 } 44 if (hasValue) 45 { 46 dt.Rows.Add(dr); 47 } 48 } 49 } 50 return dt; 51 }
四、對單元格數據類型的操作
獲取目標單元格的數據類型及數據值。
1 /// <summary> 2 /// 獲取單元格類型 3 /// </summary> 4 /// <param name="cell">目標單元格</param> 5 /// <returns></returns> 6 private static object GetValueType(ICell cell) 7 { 8 if (cell == null) 9 return null; 10 switch (cell.CellType) 11 { 12 case CellType.Blank: 13 return null; 14 case CellType.Boolean: 15 return cell.BooleanCellValue; 16 case CellType.Numeric: 17 return cell.NumericCellValue; 18 case CellType.String: 19 return cell.StringCellValue; 20 case CellType.Error: 21 return cell.ErrorCellValue; 22 case CellType.Formula: 23 default: 24 return "=" + cell.CellFormula; 25 } 26 }
將數據設置到目標單元格中，並設置為指定數據格式。
1 /// <summary> 2 /// 設置單元格數據類型 3 /// </summary> 4 /// <param name="cell">目標單元格</param> 5 /// <param name="obj">數據值</param> 6 /// <returns></returns> 7 public static void SetCellValue(ICell cell, object obj) 8 { 9 if (obj.GetType() == typeof(int)) 10 { 11 cell.SetCellValue((int)obj); 12 } 13 else if (obj.GetType() == typeof(double)) 14 { 15 cell.SetCellValue((double)obj); 16 } 17 else if (obj.GetType() == typeof(IRichTextString)) 18 { 19 cell.SetCellValue((IRichTextString)obj); 20 } 21 else if (obj.GetType() == typeof(string)) 22 { 23 cell.SetCellValue(obj.ToString()); 24 } 25 else if (obj.GetType() == typeof(DateTime)) 26 { 27 cell.SetCellValue((DateTime)obj); 28 } 29 else if (obj.GetType() == typeof(bool)) 30 { 31 cell.SetCellValue((bool)obj); 32 } 33 else 34 { 35 cell.SetCellValue(obj.ToString()); 36 } 37 }
本文地址：https://www.cnblogs.com/CKExp/p/9626022.html
2018-09-11,望技術有成后能回來看見自己的腳步