NPOI对Excel的操作（Sheet转DataTable、List<T>）

通过NPOI对Excel进行操作，这里主要是读取的操作。封装到ExcelHelper操作类中。

  1 using System.Collections.Generic;
  2 using NPOI.HSSF.UserModel;
  3 using NPOI.SS.UserModel;
  4 using NPOI.XSSF.UserModel;
  5 using System.IO;
  6 using System.Data;
  7 using System;
  8 
  9 namespace CommonHelper
 10 {
 11    public class ExcelHelper 
 12     {
 13 
 14        public ExcelHelper() { }
 15 
 16        /// <summary>
 17        /// 文件流初始化对象
 18        /// </summary>
 19        /// <param name="stream"></param>
 20        public ExcelHelper(Stream stream) 
 21        {
 22            _IWorkbook = CreateWorkbook(stream);
 23        }
 24 
 25        /// <summary>
 26        /// 传入文件名
 27        /// </summary>
 28        /// <param name="fileName"></param>
 29        public ExcelHelper(string fileName) 
 30        {
 31            using (FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
 32            {
 33                _IWorkbook = CreateWorkbook(fileStream);
 34            }
 35        }
 36 
 37        /// <summary>
 38        /// 工作薄
 39        /// </summary>
 40        private IWorkbook _IWorkbook;
 41 
 42        /// <summary>
 43        /// 创建工作簿对象
 44        /// </summary>
 45        /// <param name="stream"></param>
 46        /// <returns></returns>
 47        private IWorkbook CreateWorkbook(Stream stream) 
 48        {
 49            try 
 50            {
 51               return new XSSFWorkbook(stream); //07
 52            }
 53            catch
 54            {
 55               return new HSSFWorkbook(stream); //03
 56            }
 57           
 58        }
 59 
 60        /// <summary>
 61        /// 把Sheet中的数据转换为DataTable
 62        /// </summary>
 63        /// <param name="sheet"></param>
 64        /// <returns></returns>
 65        private DataTable ExportToDataTable(ISheet sheet) 
 66        {
 67            DataTable dt = new DataTable();
 68 
 69            //默认，第一行是字段
 70            IRow headRow = sheet.GetRow(0);
 71 
 72            //设置datatable字段
 73            for (int i = headRow.FirstCellNum, len = headRow.LastCellNum; i < len; i++)
 74            {
 75                dt.Columns.Add(headRow.Cells[i].StringCellValue);
 76            }
 77            //遍历数据行
 78            for (int i = (sheet.FirstRowNum + 1), len = sheet.LastRowNum + 1; i < len; i++)
 79            {
 80                IRow tempRow = sheet.GetRow(i);
 81                DataRow dataRow = dt.NewRow();
 82 
 83                //遍历一行的每一个单元格
 84                for (int r = 0, j = tempRow.FirstCellNum, len2 = tempRow.LastCellNum; j < len2; j++, r++)
 85                {
 86 
 87                    ICell cell = tempRow.GetCell(j);
 88 
 89                    if (cell != null)
 90                    {
 91                        switch (cell.CellType)
 92                        {
 93                            case CellType.STRING:
 94                                dataRow[r] = cell.StringCellValue;
 95                                break;
 96                            case CellType.NUMERIC:
 97                                dataRow[r] = cell.NumericCellValue;
 98                                break;
 99                            case CellType.BOOLEAN:
100                                dataRow[r] = cell.BooleanCellValue;
101                                break;
102                            default: dataRow[r] = "ERROR";
103                                break;
104                        }
105                    }
106                }
107                dt.Rows.Add(dataRow);
108            }
109            return dt;
110        }
111 
112        /// <summary>
113        /// Sheet中的数据转换为List集合
114        /// </summary>
115        /// <param name="sheet"></param>
116        /// <param name="fields"></param>
117        /// <returns></returns>
118        private IList<T> ExportToList<T>(ISheet sheet,string[] fields) where T:class,new()
119        {
120             IList<T> list = new List<T>();
121 
122            //遍历每一行数据
123            for (int i = sheet.FirstRowNum + 1, len = sheet.LastRowNum + 1; i < len; i++) 
124            {
125                T t=new T();
126                IRow row = sheet.GetRow(i);
127 
128                for (int j = 0, len2 = fields.Length; j < len2; j++)
129                {
130                    ICell cell=row.GetCell(j);
131                    object cellValue= null;
132 
133                    switch (cell.CellType) 
134                    {
135                        case CellType.STRING: //文本
136                            cellValue = cell.StringCellValue;
137                            break;
138                        case CellType.NUMERIC: //数值
139                            cellValue =Convert.ToInt32(cell.NumericCellValue);//Double转换为int
140                            break;
141                        case CellType.BOOLEAN: //bool
142                            cellValue = cell.BooleanCellValue;
143                            break;
144                        case CellType.BLANK: //空白
145                            cellValue = "";
146                            break;
147                        default: cellValue = "ERROR";
148                            break;
149                    }
150 
151                    typeof(T).GetProperty(fields[j]).SetValue(t,cellValue,null);
152                }
153                list.Add(t);
154            }
155 
156                return list;
157        }
158 
159        /// <summary>
160        /// 获取第一个Sheet的第X行，第Y列的值。起始点为1
161        /// </summary>
162        /// <param name="X">行</param>
163        /// <param name="Y">列</param>
164        /// <returns></returns>
165        public string GetCellValue(int X, int Y) 
166        {
167            ISheet sheet = _IWorkbook.GetSheetAt(0);
168 
169            IRow row = sheet.GetRow(X-1);
170 
171            return row.GetCell(Y-1).ToString();
172        }
173 
174        /// <summary>
175        /// 获取一行的所有数据
176        /// </summary>
177        /// <param name="X">第x行</param>
178        /// <returns></returns>
179        public string[] GetCells(int X) 
180        {
181            List<string> list = new List<string>();
182 
183            ISheet sheet = _IWorkbook.GetSheetAt(0);
184 
185            IRow row = sheet.GetRow(X-1);
186 
187            for (int i = 0, len = row.LastCellNum; i < len; i++) 
188            {
189                list.Add(row.GetCell(i).StringCellValue);//这里没有考虑数据格式转换，会出现bug
190            }
191            return list.ToArray();
192        }
193 
194        /// <summary>
195        /// 第一个Sheet数据，转换为DataTable
196        /// </summary>
197        /// <returns></returns>
198        public DataTable ExportExcelToDataTable() 
199        {
200            return ExportToDataTable(_IWorkbook.GetSheetAt(0));
201        }
202 
203        /// <summary>
204        /// 第sheetIndex表数据，转换为DataTable
205        /// </summary>
206        /// <param name="sheetIndex">第几个Sheet，从1开始</param>
207        /// <returns></returns>
208        public DataTable ExportExcelToDataTable(int sheetIndex) 
209        {
210            return ExportToDataTable(_IWorkbook.GetSheetAt(sheetIndex-1));
211        }
212 
213 
214        /// <summary>
215        /// Excel中默认第一张Sheet导出到集合
216        /// </summary>
217        /// <param name="fields">Excel各个列，依次要转换成为的对象字段名称</param>
218        /// <returns></returns>
219        public IList<T> ExcelToList<T>(string[] fields) where T:class,new ()
220        {
221            return ExportToList<T>(_IWorkbook.GetSheetAt(0),fields);
222        }
223 
224        /// <summary>
225        /// Excel中指定的Sheet导出到集合
226        /// </summary>
227        /// <param name="sheetIndex">第几张Sheet,从1开始</param>
228        /// <param name="fields">Excel各个列，依次要转换成为的对象字段名称</param>
229        /// <returns></returns>
230        public IList<T> ExcelToList<T>(int sheetIndex,string[] fields) where T:class,new()
231        {
232           return ExportToList<T>(_IWorkbook.GetSheetAt(sheetIndex-1), fields);
233        }
234 
235     }
236 }