c#(NPOI)DataTable导出execl，execl(支持解析公式)导入DataTable

NPOI(C#)DataTable导出execl

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System;
using NPOI.SS.Util;
namespace Common
{
/// <summary>
    /// 使用NPOI操作Excel，无需Office COM组件
    /// </summary>
    public class ExcelHelper
    {
/// <summary>
        /// DataTable转换成Excel文档流，并输出到客户端，如果设置表名请设置table.TableName="表名"
        /// </summary>
        /// <param name="table">DataTable</param>
        /// <param name="context">上下文对象</param>
        /// <param name="fileName">Excel文件名(为空以当前时间加随机数命名)</param>
        public static void RenderToExcel(DataTable table, HttpContext context, string fileName=null)
        {
            var name = "";
            if (fileName==""&&fileName==null)
            {
                name = DateTime.Now.ToString("yyyyMMddhhmmss") + new Random(DateTime.Now.Second).Next(10000);
            }
            else
            {
                name = fileName + new Random(DateTime.Now.Second).Next(10000);
            }

            var path = context.Server.MapPath("~/xls_down/" + name + ".xls");
            if (!Directory.Exists(context.Server.MapPath("~/xls_down")))
            {
                Directory.CreateDirectory(context.Server.MapPath("~/xls_down"));
            }
            else
            {
                //DeleteAllFile(context.Server.MapPath("~/xls_down"));
            }
            TableToExcelForXLS(table, path, fileName);

            System.IO.FileInfo file = new System.IO.FileInfo(path);
            context.Response.ContentType = "application/ms-download";
            context.Response.Clear();
            context.Response.AddHeader("Content-Type", "application/octet-stream");
            context.Response.Charset = "utf-8";
            context.Response.AddHeader("Content-Disposition", "attachment;filename=" + System.Web.HttpUtility.UrlEncode(file.Name, System.Text.Encoding.UTF8));
            context.Response.AddHeader("Content-Length", file.Length.ToString());
            context.Response.WriteFile(file.FullName);
            context.Response.Flush();
            context.Response.Clear();
            context.Response.End();
        }
        /// <summary>
            /// 将DataTable数据导出到Excel文件中(xls)
            /// </summary>
            /// <param name="dt"></param>
            /// <param name="file">路径</param>
            /// <param name="tablename">表名</param>
            public void TableToExcelForXLS(DataTable dt, string file,string tablename=null)
            {
                HSSFWorkbook hssfworkbook = new HSSFWorkbook();

                if (tablename == null)
                    tablename = "table1";
                ISheet sheet = hssfworkbook.CreateSheet(tablename);
                int n = 0;  //控制表名,在第一行(列名前面一行)显示

                if (dt.TableName != null && dt.TableName!="")
                {
                    //表名
                    //设置一个合并单元格区域，使用上下左右定义CellRangeAddress区域
                    //CellRangeAddress四个参数为：起始行，结束行，起始列，结束列
                    sheet.AddMergedRegion(new CellRangeAddress(0, 0, 0, dt.Columns.Count));
                    IRow rowtitle = sheet.CreateRow(0);

                    ICell celltitle = rowtitle.CreateCell(0);
                    celltitle.SetCellValue(dt.TableName);
                    //设置单元格样式时需要注意，务必创建一个新的样式对象进行设置，否则会将工作表所有单元格的样式一同设置，它们应该共享的是一个样式对象
                    ICellStyle style = hssfworkbook.CreateCellStyle();
                    //设置单元格的样式：水平对齐居中
                    style.Alignment = HorizontalAlignment.Center;
                    //新建一个字体样式对象
                    IFont font = hssfworkbook.CreateFont();
                    //设置字体加粗样式
                    font.Boldweight = short.MaxValue;
                    //使用SetFont方法将字体样式添加到单元格样式中
                    style.SetFont(font);
                    //将新的样式赋给单元格
                    celltitle.CellStyle = style;
                    n = 1;  //添加表名之后置为1
                }

                int[] ColumnWidthArray = new int[dt.Columns.Count]; //列宽数组(自适应列宽)
                //表头
                IRow row = sheet.CreateRow(n);
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    ICell cell = row.CreateCell(i);
                    cell.SetCellValue(dt.Columns[i].ColumnName);
                    //可以获取中文长度，中文占2个字符
                    ColumnWidthArray[i] = System.Text.Encoding.Default.GetBytes(dt.Columns[i].ColumnName).Length;
                }

                //数据
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    IRow row1 = sheet.CreateRow(i + n+1);
                    for (int j = 0; j < dt.Columns.Count; j++)
                    {
                        ICell cell = row1.CreateCell(j);
                        String cellValue=dt.Rows[i][j].ToString();
                        cell.SetCellValue(cellValue);
                        if (System.Text.Encoding.Default.GetBytes(cellValue).Length > ColumnWidthArray[j])
                        {
                            ColumnWidthArray[j] = System.Text.Encoding.Default.GetBytes(cellValue).Length;
                        }
                    }
                }
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    sheet.SetColumnWidth(i, (ColumnWidthArray[i]+2) * 256);
                }
                //转为字节数组
                MemoryStream stream = new MemoryStream();
                hssfworkbook.Write(stream);
                var buf = stream.ToArray();

                //保存为Excel文件
                using (FileStream fs = new FileStream(file, FileMode.Create, FileAccess.Write))
                {
                    fs.Write(buf, 0, buf.Length);
                    fs.Flush();
                }
            }
}
}

execl(支持解析公式)导入DataTable

  1             /// <summary>
  2             /// 将Excel文件中的数据读出到DataTable中(xls)
  3             /// </summary>
  4             /// <param name="file">文件绝对路径</param>
  5             /// <returns></returns>
  6             public static DataTable ExcelToTableForXLS(string file, int sheetIndex = 0)
  7             {
  8                 DataTable dt = new DataTable();
  9                 using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read))
 10                 {
 11                     HSSFWorkbook hssfworkbook = new HSSFWorkbook(fs);
 12                     ISheet sheet = hssfworkbook.GetSheetAt(sheetIndex);
 13
 14                     //表头
 15                     IRow header = sheet.GetRow(sheet.FirstRowNum);
 16                     List<int> columns = new List<int>();
 17                     for (int i = 0; i < header.LastCellNum; i++)
 18                     {
 19                         object obj = GetValueTypeForXLS(header.GetCell(i) as HSSFCell);
 20                         if (obj == null || obj.ToString() == string.Empty)
 21                         {
 22                             dt.Columns.Add(new DataColumn("Columns" + i.ToString()));
 23                             //continue;
 24                         }
 25                         else
 26                             dt.Columns.Add(new DataColumn(obj.ToString()));
 27                         columns.Add(i);
 28                     }
 29                     //数据
 30                     for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum; i++)
 31                     {
 32                         IRow row = sheet.GetRow(i);
 33
 34                         if (row != null)
 35                         {
 36                             DataRow dr = dt.NewRow();
 37                             bool hasValue = false;
 38                             foreach (int j in columns)
 39                             {
 40                                 dr[j] = GetValueTypeForXLS(sheet.GetRow(i).GetCell(j) as HSSFCell);
 41                                 #region 增加格式解析
 42                                 if (row.GetCell(j) != null)
 43                                 {
 44                                     switch (row.GetCell(j).CellType)
 45                                     {
 46                                         case CellType.Numeric:
 47                                             if (HSSFDateUtil.IsCellDateFormatted(row.GetCell(j)))//日期类型
 48                                             {
 49                                                 dr[j] = row.GetCell(j).DateCellValue.ToString("yyyy-MM-dd");
 50                                             }
 51                                             else//其他数字类型
 52                                             {
 53                                                 dr[j] = row.GetCell(j).NumericCellValue;
 54                                             }
 55                                             break;
 56                                         case CellType.Blank:
 57                                             dr[j] = string.Empty;
 58                                             break;
 59                                         case CellType.Formula:
 60                                             if (Path.GetExtension(file).ToLower().Trim() == ".xlsx")
 61                                             {
 62                                                 XSSFFormulaEvaluator eva = new XSSFFormulaEvaluator(hssfworkbook);
 63                                                 if (eva.Evaluate(row.GetCell(j)).CellType == CellType.Numeric)
 64                                                 {
 65                                                     if (HSSFDateUtil.IsCellDateFormatted(row.GetCell(j)))//日期类型
 66                                                     {
 67                                                         dr[j] = row.GetCell(j).DateCellValue.ToString("yyyy-MM-dd");
 68                                                     }
 69                                                     else//其他数字类型
 70                                                     {
 71                                                         dr[j] = row.GetCell(j).NumericCellValue;
 72                                                     }
 73                                                 }
 74                                                 else
 75                                                 {
 76                                                     dr[j] = eva.Evaluate(row.GetCell(j)).StringValue;
 77                                                 }
 78                                             }
 79                                             else
 80                                             {
 81                                                 HSSFFormulaEvaluator eva = new HSSFFormulaEvaluator(hssfworkbook);
 82                                                 if (eva.Evaluate(row.GetCell(j)).CellType == CellType.Numeric)
 83                                                 {
 84                                                     if (HSSFDateUtil.IsCellDateFormatted(row.GetCell(j)))//日期类型
 85                                                     {
 86                                                         dr[j] = row.GetCell(j).DateCellValue.ToString("yyyy-MM-dd");
 87                                                     }
 88                                                     else//其他数字类型
 89                                                     {
 90                                                         dr[j] = row.GetCell(j).NumericCellValue;
 91                                                     }
 92                                                 }
 93                                                 else
 94                                                 {
 95                                                     dr[j] = eva.Evaluate(row.GetCell(j)).StringValue;
 96                                                 }
 97                                             }
 98                                             break;
 99                                         default:
100                                             dr[j] = row.GetCell(j).StringCellValue;
101                                             break;
102
103                                     }
104                                 }
105                                 #endregion
106
107                                 if (dr[j] != null && dr[j].ToString() != string.Empty)
108                                 {
109                                     hasValue = true;
110                                 }
111                             }
112                             if (hasValue)
113                             {
114                                 dt.Rows.Add(dr);
115                             }
116                         }
117                     }
118                 }
119
120                 return dt;
121             }