NPOI对Excel的操作（Sheet转DataTable、List）

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 }