使用NPOI操作Excel文件及其日期处理

工作中经常遇到需要读取或导出Excel文件的情况，而NPOI是目前最宜用、效率最高的操作的Office（不只是Excel哟）文件的组件，使用方便，不详细说明了。

Excel工作表约定：整个Excel表格叫做工作表：WorkBook（工作薄），包含的叫页（工作表）：Sheet；行：Row；单元格Cell。

1、先上一个Excel2003的例子，代码如下：

//读取xls文件         private void button2_Click(object sender, EventArgs e)         {   StringBuilder sbr = new StringBuilder();             using (FileStream fs = File.OpenRead(@"c:/myxls.xls"))   //打开myxls.xls文件             {                 HSSFWorkbook wk = new HSSFWorkbook(fs);   //把xls文件中的数据写入wk中                 for (int i = 0; i < wk.NumberOfSheets; i++)  //NumberOfSheets是myxls.xls中总共的表数                 {                     ISheet sheet = wk.GetSheetAt(i);   //读取当前表数据                     for (int j = 0; j <= sheet.LastRowNum; j++)  //LastRowNum 是当前表的总行数                     {                         IRow row = sheet.GetRow(j);  //读取当前行数据                         if (row != null)                         {                             sbr.Append("-------------------------------------\r\n"); //读取行与行之间的提示界限                             for (int k = 0; k <= row.LastCellNum; k++)  //LastCellNum 是当前行的总列数                             {                                 ICell cell = row.GetCell(k);  //当前表格                                 if (cell != null)                                 {                                                                        sbr.Append(cell.ToString());   //获取表格中的数据并转换为字符串类型                                 }                             }                         }                     }                 }                            }             sbr.ToString();             using (StreamWriter wr = new StreamWriter(new FileStream(@"c:/myText.txt", FileMode.Append)))  //把读取xls文件的数据写入myText.txt文件中             {                 wr.Write(sbr.ToString());                 wr.Flush();             }         }

//创建一个常用的xls文件         private void button3_Click(object sender, EventArgs e)         {                       IWorkbook wb = new HSSFWorkbook();             //创建表               ISheet sh = wb.CreateSheet("zhiyuan");             //设置单元的宽度               sh.SetColumnWidth(0, 15 * 256);             sh.SetColumnWidth(1, 35 * 256);             sh.SetColumnWidth(2, 15 * 256);             sh.SetColumnWidth(3, 10 * 256);             int i = 0;             #region 练习合并单元格             sh.AddMergedRegion(new NPOI.SS.Util.CellRangeAddress(0, 0, 0, 3));

//CellRangeAddress（）该方法的参数次序是：开始行号，结束行号，开始列号，结束列号。             IRow row0 = sh.CreateRow(0);             row0.Height = 20 * 20;             ICell icell1top0 = row0.CreateCell(0);             icell1top0.CellStyle = Getcellstyle(wb, stylexls.头);             icell1top0.SetCellValue("标题合并单元");             #endregion             i++;             #region 设置表头             IRow row1 = sh.CreateRow(1);             row1.Height = 20 * 20;

ICell icell1top = row1.CreateCell(0);             icell1top.CellStyle = Getcellstyle(wb, stylexls.头);             icell1top.SetCellValue("网站名");

ICell icell2top = row1.CreateCell(1);             icell2top.CellStyle = Getcellstyle(wb, stylexls.头);             icell2top.SetCellValue("网址");

ICell icell3top = row1.CreateCell(2);             icell3top.CellStyle = Getcellstyle(wb, stylexls.头);             icell3top.SetCellValue("百度快照");

ICell icell4top = row1.CreateCell(3);             icell4top.CellStyle = Getcellstyle(wb, stylexls.头);             icell4top.SetCellValue("百度收录");             #endregion               using(FileStream stm=File.OpenWrite(@"c:/myMergeCell.xls"))             {                 wb.Write(stm);                  MessageBox.Show("提示：创建成功！");             }         }

#region 定义单元格常用到样式的枚举         public enum stylexls         {             头,             url,             时间,             数字,             钱,             百分比,             中文大写,             科学计数法,             默认         }         #endregion

#region 定义单元格常用到样式         static ICellStyle Getcellstyle(IWorkbook wb, stylexls str)         {             ICellStyle cellStyle = wb.CreateCellStyle();

//定义几种字体               //也可以一种字体，写一些公共属性，然后在下面需要时加特殊的               IFont font12 = wb.CreateFont();             font12.FontHeightInPoints = 10;             font12.FontName = "微软雅黑";

IFont font = wb.CreateFont();             font.FontName = "微软雅黑";             //font.Underline = 1;下划线

IFont fontcolorblue = wb.CreateFont();             fontcolorblue.Color = HSSFColor.OLIVE_GREEN.BLUE.index;             fontcolorblue.IsItalic = true;//下划线               fontcolorblue.FontName = "微软雅黑";

//边框               cellStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.DOTTED;             cellStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.HAIR;             cellStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.HAIR;             cellStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.DOTTED;             //边框颜色               cellStyle.BottomBorderColor = HSSFColor.OLIVE_GREEN.BLUE.index;             cellStyle.TopBorderColor = HSSFColor.OLIVE_GREEN.BLUE.index;

//背景图形，我没有用到过。感觉很丑               //cellStyle.FillBackgroundColor = HSSFColor.OLIVE_GREEN.BLUE.index;               //cellStyle.FillForegroundColor = HSSFColor.OLIVE_GREEN.BLUE.index;               cellStyle.FillForegroundColor = HSSFColor.WHITE.index;             // cellStyle.FillPattern = FillPatternType.NO_FILL;               cellStyle.FillBackgroundColor = HSSFColor.BLUE.index;

//水平对齐               cellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.LEFT;

//垂直对齐               cellStyle.VerticalAlignment = VerticalAlignment.CENTER;

//自动换行               cellStyle.WrapText = true;

//缩进;当设置为1时，前面留的空白太大了。希旺官网改进。或者是我设置的不对               cellStyle.Indention = 0;

//上面基本都是设共公的设置

//下面列出了常用的字段类型               switch (str)             {                 case stylexls.头:                     // cellStyle.FillPattern = FillPatternType.LEAST_DOTS;                       cellStyle.SetFont(font12);                     break;                 case stylexls.时间:                     IDataFormat datastyle = wb.CreateDataFormat();

cellStyle.DataFormat = datastyle.GetFormat("yyyy/mm/dd");                     cellStyle.SetFont(font);                     break;                 case stylexls.数字:                     cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("0.00");                     cellStyle.SetFont(font);                     break;                 case stylexls.钱:                     IDataFormat format = wb.CreateDataFormat();                     cellStyle.DataFormat = format.GetFormat("￥#,##0");                     cellStyle.SetFont(font);                     break;                 case stylexls.url:                     fontcolorblue.Underline = 1;                     cellStyle.SetFont(fontcolorblue);                     break;                 case stylexls.百分比:                     cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("0.00%");                     cellStyle.SetFont(font);                     break;                 case stylexls.中文大写:                     IDataFormat format1 = wb.CreateDataFormat();                     cellStyle.DataFormat = format1.GetFormat("[DbNum2][$-804]0");                     cellStyle.SetFont(font);                     break;                 case stylexls.科学计数法:                     cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("0.00E+00");                     cellStyle.SetFont(font);                     break;                 case stylexls.默认:                     cellStyle.SetFont(font);                     break;             }             return cellStyle;

}         #endregion

2、再来一个Excel2007的并绑定到GridView中例子，代码如下：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Data;

using System.IO;

using NPOI.SS.UserModel;

using NPOI.HSSF.Util;

using NPOI.HSSF.UserModel;

using NPOI.XSSF.UserModel;

/// <summary>

///NPOI操作Excel，这个例子是针对Excel 2007.

/// </summary>

public class ExcelHelper{

IWorkbook hssfworkbook;

public DataTable ImportExcelFile(string filePath)

{

#region//初始化信息

try

{

using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))

{

hssfworkbook = new XSSFWorkbook(file);

}

}

catch (Exception e)

{

throw e;

}

#endregion

ISheet sheet = hssfworkbook.GetSheetAt(0);

System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

DataTable dt = new DataTable();

//一行最后一个方格的编号 即总的列数

for (int j = 0; j < (sheet.GetRow(0).LastCellNum); j++)

{

dt.Columns.Add(Convert.ToChar(((int)'A') + j).ToString());

}

while (rows.MoveNext())

{

IRow row = (XSSFRow)rows.Current;

DataRow dr = dt.NewRow();

for (int i = 0; i < row.LastCellNum; i++)

{

ICell cell = row.GetCell(i);

if (cell == null)

{

dr[i] = null;

}

else

{

dr[i] = cell.ToString();

}

}

dt.Rows.Add(dr);

}

return dt;

}

hssfworkbook= null;

sheet = null;

}

//绑定GridView显示只需要两名代码

this.gvExcel.DataSource = dt;

this.gvExcel.DataBind();

3、NPOI中的日期处理，NOPI版本为2.0.2。

POI对单元格日期处理很弱，没有针对的类型，日期类型取出来的也是一个double值，所以同样作为数值类型。

/**

*Excel中的日期格式在解析为DataTable时会依格式不同解析为不同的值，因为所有的日期格式都可以通过下面DataFormat来判断，

*excel2013，测试结果如下：*时分(HH:mm) - 20，时间(HH:mm:ss) - 21，日期时间(yyyy-MM-dd HH:mm:ss) - 22，

*年月(yyyy-MM) - 17，年月日(yyyy-MM-dd)-14，yyyy年m月-------57，月日(MM-dd) - 58，

*yyyy年m月d日---31，h时mm分  -------32

* */

if (cell.CellType == CellType.NUMERIC)

{

short format = cell.CellStyle.DataFormat;

if (format == 14 || format == 31 || format == 57 || format == 58)

{

DateTime date = cell.DateCellValue;

string re = date.ToString("yyy-MM-dd");

}

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