Excel导入导出在项目运用中并不少见，传统的情况一般都是采用插件的形式走流程，像这种的网上一大把就不再复述。这里就写出完整的思路以及代码，供大家借鉴。
一、添加引用dotnet4（网上有，可以自行下载）
二、添加导入导出类Entities.cs
1 public class Entities:IDisposable
2 {
3 private string fileName = null; //文件名
4 private static IWorkbook workbook = null;
5 private static FileStream fs = null;
6 private bool disposed;
7
8 public Entities(string fileName)
9 {
10 this.fileName = fileName;
11 disposed = false;
12
13 }
14
15 #region 将excel中的数据导入到DataTable中
16 /// <summary>
17 /// 将excel中的数据导入到DataTable中
18 /// </summary>
19 /// <param name="fileNameurl">表名</param>
20 /// <param name="sheetName">excel工作薄sheet的名称</param>
21 /// <returns>返回的DataTable</returns>
22 public static DataTable ExcelToDataTableHelper(string fileNameurl, string sheetName)
23 {
24 return ExcelToDataTableHelper(fileNameurl, sheetName, 1);
25 }
26
27 /// <summary>
28 /// 将excel中的数据导入到DataTable中
29 /// </summary>
30 /// <param name="fileNameurl">表名</param>
31 /// <param name="sheetName">excel工作薄sheet的名称</param>
32 /// <param name="ColumnNum">第几行是表头</param>
33 /// <returns>返回的DataTable</returns>
34 public static DataTable ExcelToDataTableHelper(string fileNameurl, string sheetName, int ColumnNum)
35 {
36 ISheet sheet = null;
37 DataTable data = new DataTable();
38 int startRow = 0;
39 try
40 {
41 fs = new FileStream(fileNameurl, FileMode.Open, FileAccess.Read);
42 if (fileNameurl.IndexOf(".xlsx") > 0) // 2007版本
43 workbook = new XSSFWorkbook(fs);
44 else if (fileNameurl.IndexOf(".xls") > 0) // 2003版本
45 workbook = new HSSFWorkbook(fs);
46
47 if (sheetName != null)
48 {
49 sheet = workbook.GetSheet(sheetName);
50 if (sheet == null) //如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
51 {
52 sheet = workbook.GetSheetAt(0);
53 }
54 }
55 else
56 {
57 sheet = workbook.GetSheetAt(0);
58 }
59 if (sheet != null)
60 {
61 IRow firstRow;
62
63 // firstRow = sheet.GetRow(0);
64 if (ColumnNum > 0)
65 {
66 firstRow = sheet.GetRow(ColumnNum - 1);
67 }
68 else
69 {
70 firstRow = sheet.GetRow(0);
71 }
72 int cellCount = firstRow.LastCellNum; //一行最后一个cell的编号 即总的列数
73
74 for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
75 {
76 ICell cell = firstRow.GetCell(i);
77 if (cell != null)
78 {
79 string cellValue = cell.StringCellValue;
80 if (cellValue != null && cellValue != "")
81 {
82 DataColumn column = new DataColumn(cellValue);
83 data.Columns.Add(column);
84 }
85 }
86 }
87 cellCount = data.Columns.Count;
88
89 //找出第几行是列名
90 startRow = ColumnNum;
91
92 //startRow = firstDataNum-1;
93 //最后一列的标号
94 int rowCount = sheet.LastRowNum;
95 for (int i = startRow; i <= rowCount; ++i)
96 {
97 IRow row = sheet.GetRow(i);
98 if (row == null) continue; //没有数据的行默认是null
99 DataRow dataRow = data.NewRow();
100 for (int j = row.FirstCellNum; j < cellCount; ++j)
101 {
102 if (row.GetCell(j) != null) //同理，没有数据的单元格都默认是null
103 {
104 //dataRow[j] = row.GetCell(j).ToString();
105 //读取Excel格式，根据格式读取数据类型
106 ICell cell = row.GetCell(j);
107 dataRow[j] = parseExcel(cell);
108 }
109 }
110 data.Rows.Add(dataRow);
111 }
112 }
113 return data;
114 }
115 catch (Exception ex)
116 {
117 Console.WriteLine("Exception: " + ex.Message);
118 return null;
119 }
120 finally
121 {
122 if (fs != null)
123 fs.Close();
124 }
125 }
126
127 //格式转换
128 private static String parseExcel(ICell cell)
129 {
130 string result = "";
131 switch (cell.CellType)
132 {
133 case CellType.Formula:
134 HSSFFormulaEvaluator e = new HSSFFormulaEvaluator(workbook);
135 result = e.Evaluate(cell).StringValue;
136 break;
137 case CellType.Numeric:// 数字类型
138 if (HSSFDateUtil.IsCellDateFormatted(cell))
139 {// 处理日期格式、时间格式
140 string sdf = "";
141 if (cell.CellStyle.DataFormat == HSSFDataFormat
142 .GetBuiltinFormat("h:mm"))
143 {
144 sdf = "HH:mm";
145 }
146 else
147 {// 日期
148 sdf = "yyyy-MM-dd";
149 }
150 DateTime date = cell.DateCellValue;
151 result = date.ToString(sdf);
152 }
153 else if (cell.CellStyle.DataFormat == 58)
154 {
155 // 处理自定义日期格式：m月d日(通过判断单元格的格式id解决，id的值是58)
156 string sdf = "yyyy-MM-dd";
157 double value = cell.NumericCellValue;
158 DateTime date = new DateTime(1899, 12, 30); // 起始时间
159 date = date.AddDays(value);
160 result = date.ToString(sdf);
161 }
162 else
163 {
164 result = cell.NumericCellValue.ToString();
165 }
166 break;
167 case CellType.String:// String类型
168 result = cell.StringCellValue;
169 break;
170 case CellType.Blank:
171 result = "";
172 break;
173 default:
174 result = "";
175 break;
176 }
177 return result;
178 }
179
180 /// <summary>
181 /// 获取Exce工作薄名称
182 /// </summary>
183 /// <param name="fileNameurl"></param>
184 /// <returns></returns>
185 public static List<string> GetSheetNames(string fileNameurl)
186 {
187 using (FileStream sr = new FileStream(fileNameurl, FileMode.OpenOrCreate))
188 {
189 //根据路径通过已存在的excel来创建HSSFWorkbook，即整个excel文档
190 HSSFWorkbook workbook = new HSSFWorkbook(sr);
191 int x = workbook.Workbook.NumSheets;
192 List<string> sheetNames = new List<string>();
193 for (int i = 0; i < x; i++)
194 {
195 sheetNames.Add(workbook.Workbook.GetSheetName(i));
196 }
197 return sheetNames;
198 }
199 }
200
201 //资源释放
202 public void Dispose()
203 {
204 //释放资源
205 Dispose(true);
206 //告诉垃圾回收器不要调用指定对象的Dispose方法
207 GC.SuppressFinalize(this);
208 }
209
210 protected virtual void Dispose(bool disposing)
211 {
212 if (!this.disposed)
213 {
214 if (disposing)
215 {
216 if (fs != null)
217 fs.Close();
218 }
219
220 fs = null;
221 disposed = true;
222 }
223 }
224 #endregion
225 }
将Entities类作为导入导出Excel的中枢
三、上传Excel模版
选好模版后将之放入文件夹，通过Upload方法实现模版下载
1 [HttpPost]
2 public ActionResult Upload(HttpPostedFileBase file)
3 {
4 if (file == null)
5 {
6 return Content("没有文件！", "text/plain");
7 }
8 var fileName = Path.Combine(Request.MapPath("~/Upload"), Path.GetFileName(file.FileName));
9 //string strFilePaht = "~/Upload";
10 //string filename = Path.GetFileNameWithoutExtension(fileName); //这个就是获取文件名的
11 Session["filename"] = fileName;
12 try
13 {
14 file.SaveAs(fileName);
15 Response.Write("<script>alert('上传成功')</script>");
16 }
17 catch
18 {
19 return Content("上传异常 ！", "text/plain");
20 }
21 return View();
22 }
这里只是一个简单的文件下载逻辑，后面有待完善
四、当下载好模版后将需要导入的Excel数据使用Import方法导入到DataTable，存入到数据库
1 public ActionResult Import()
2 {
3 //继承来自上传文件的文件路径 ，该路径为相对路径
4 string pathName = Session["filename"].ToString();
5 if (pathName=="")
6 {
7 return Json("erro",JsonRequestBehavior.AllowGet);
8 }
9 string sheet = "Sheet1";
10 //传入参数,将excel转换为Datatable，格式文件名加上固定模版Sheet1
11 DataTable dt = Infotype.ExcelHelper.Entities.ExcelToDataTableHelper(pathName, sheet);
12 //循环这个集合并添加到数据表
13 int i = 0;
14 foreach (DataRow item in dt.Rows)
15 {
16 tab.ProjectName = item[0].ToString();
17 tab.InfoTypes = item[1].ToString();
18 tab.field = item[2].ToString();
19 tab.fieldtxt = item[3].ToString();
20 db.InfoTables.Add(tab);
21 i = db.SaveChanges();
22 }
23 if (i > 0)
24 {
25 return Json("Data", JsonRequestBehavior.AllowGet);
26 }
27 else
28 {
29 return Json("NOData", JsonRequestBehavior.AllowGet);
30 }
31
32 }
五、当修改了数据需要及时导出到Excel时就可以用到ExportStu2导出了
1 public FileResult ExportStu2()
2 {
3 //获取list数据
4 var checkList = db.InfoTables.Where(r => r.ProjectName != null).Select(r => new { r.ProjectName,r.InfoTypes,r.field,r.fieldtxt }).ToList();
5 //创建Excel文件的对象
6 NPOI.HSSF.UserModel.HSSFWorkbook book = new NPOI.HSSF.UserModel.HSSFWorkbook();
7 //添加一个sheet
8 NPOI.SS.UserModel.ISheet sheet1 = book.CreateSheet("Sheet1");
9
10 //给sheet1添加第一行的头部标题
11 NPOI.SS.UserModel.IRow row1 = sheet1.CreateRow(0);
12 row1.CreateCell(0).SetCellValue("项目名称");
13 row1.CreateCell(1).SetCellValue("信息类型");
14 row1.CreateCell(2).SetCellValue("字段");
15 row1.CreateCell(3).SetCellValue("字段名称");
16 //....N行
17
18 //将数据逐步写入sheet1各个行
19 for (int i = 0; i < checkList.Count(); i++)
20 {
21 NPOI.SS.UserModel.IRow rowtemp = sheet1.CreateRow(i + 1);
22 rowtemp.CreateCell(0).SetCellValue(checkList[i].ProjectName.ToString());
23 rowtemp.CreateCell(1).SetCellValue(checkList[i].InfoTypes.ToString());
24 rowtemp.CreateCell(2).SetCellValue(checkList[i].field.ToString());
25 rowtemp.CreateCell(3).SetCellValue(checkList[i].fieldtxt.ToString());
26 //....N行
27 }
28 // 写入到客户端
29 System.IO.MemoryStream ms = new System.IO.MemoryStream();
30 book.Write(ms);
31 ms.Seek(0, SeekOrigin.Begin);
32 DateTime dt = DateTime.Now;
33 string dateTime = dt.ToString("yyMMddHHmmssfff");
34 string fileName = "查询结果" + dateTime + ".xls";
35 return File(ms, "application/vnd.ms-excel", fileName);
36 }