C#_.NetFramework_Web项目_EXCEL数据导入

【推荐阅读我的最新的Core版文章，是最全的介绍：C#_.NetCore_Web项目_EXCEL数据导出】

需要引用NPOI的Nuget包：NPOI-v2.4.1

B-1：EXCEL数据导入--C#获取数据：

/// <summary>
        /// EXCEL帮助类
        /// </summary>
        /// <typeparam name="T">泛型类</typeparam>
        /// <typeparam name="TCollection">泛型类集合</typeparam>
        public class ExcelHelp<T, TCollection> where T : new() where TCollection : List<T>, new()
        {
            //http请求Request对象
            public static HttpRequest baseRequest = HttpContext.Current.Request;
            //http请求Response对象
            public static HttpResponse baseResponse = HttpContext.Current.Response;
            /// <summary>
            /// 将数据导出EXCEL
            /// </summary>
            /// <param name="columnNameAndShowNameDic">列名+显示名</param>
            /// <param name="tColl">数据集（tColl里的类属性名必须和字典中的列名一致）</param>
            public static void ExportExcelData(Dictionary<string, string> columnNameAndShowNameDic, TCollection tColl)
            {
                IWorkbook workbook = new HSSFWorkbook();
                ISheet worksheet = workbook.CreateSheet("sheet1");

                List<string> columnNameList = columnNameAndShowNameDic.Keys.ToList();
                List<string> showNameList = columnNameAndShowNameDic.Values.ToList();
                //设置首列显示
                IRow row1 = worksheet.GetRow(0);
                ICell cell = null;
                for (var i = 0; i < columnNameList.Count; i++)
                {
                    cell = row1.CreateCell(i);
                    cell.SetCellValue(columnNameList[i]);
                }

                Dictionary<int, PropertyInfo> indexPropertyDic = GetIndexPropertyDic(columnNameList);

                for (int i = 0; i < tColl.Count; i++)
                {
                    row1 = worksheet.GetRow(i + 1);
                    for (int j = 0; j < indexPropertyDic.Count; j++)
                    {
                        cell = row1.CreateCell(i);
                        cell.SetCellValue(indexPropertyDic[j].GetValue(tColl[i]).ToString());
                    }
                }
                
                MemoryStream ms = new MemoryStream();
                workbook.Write(ms);

                byte[] buffer = ms.GetBuffer();

                baseResponse.Clear();
                baseResponse.Buffer = true;
                baseResponse.ContentEncoding = System.Text.Encoding.UTF8;
                //baseResponse.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                baseResponse.ContentType = "application/vnd.ms-excel";
                //设置导出文件名
                baseResponse.AddHeader("content-disposition", "attachment;  filename=" + "MaintainReport" + ".xlsx");
                baseResponse.AddHeader("Content-Length", buffer.Length.ToString());

                baseResponse.BinaryWrite(buffer);
                baseResponse.Flush();
                baseResponse.End();
            }
            /// <summary>
            /// 根据属性名顺序获取对应的属性对象
            /// </summary>
            /// <param name="fieldNameList"></param>
            /// <returns></returns>
            private static Dictionary<int, PropertyInfo> GetIndexPropertyDic(List<string> fieldNameList)
            {
                Dictionary<int, PropertyInfo> indexPropertyDic = new Dictionary<int, PropertyInfo>(fieldNameList.Count);
                List<PropertyInfo> tPropertyInfoList = typeof(T).GetProperties().ToList();
                PropertyInfo propertyInfo = null;
                for (int i = 0; i < fieldNameList.Count; i++)
                {
                    propertyInfo = tPropertyInfoList.Find(m => m.Name.Equals(fieldNameList[i], StringComparison.OrdinalIgnoreCase));
                    indexPropertyDic.Add(i, propertyInfo);
                }

                return indexPropertyDic;
            }
        }