Npoi简单读写Excel

什么是NPOI ?

  简而言之,NPOI就是可以在没有Office的情况下对Word或Excel文档进行读写等操作。

使用方式 :

  1、准备NPOI的dll文件

    下载链接:https://npoi.codeplex.com/releases

  2、将下载的dll文件引入项目中

  3、引用命名空间

     

须知:

  1、Excel表格分为:WorkBook(工作薄)-> Sheet(工作表) -> 行:Row 单元格:Cell。

  2、NPOI是POI的C#版本,NPOI的行和列的index都是从0开始

  3、POI读取Excel有两种格式一个是HSSF,另一个是XSSF。 HSSF和XSSF的区别如下: 
     HSSF is the POI Project's pure Java implementation of the Excel '97(-2007) file format. 
     XSSF is the POI Project's pure Java implementation of the Excel 2007 OOXML (.xlsx) file format. 
     即:HSSF适用2007以前的版本,XSSF适用2007版本及其以上的。

       下面使用NPOI读取Excel例子:主要功能是将DataTable导入Excel,或将Excel读取到DataTable中。

代码如下:

 1       /// <summary>
 2         /// 将DataTable导入到Excel
 3         /// </summary>
 4         /// <param name="data">要导入的数据</param>
 5         /// <param name="filepath">导入的文件路径(包含文件名称)</param>
 6         /// <param name="sheename">要导入的表名</param>
 7         /// <param name="iscolumwrite">是否写入列名</param>
 8         /// <returns>导入Excel的行数</returns>
 9         public int DataTableToExcel(DataTable data, string filepath, string sheename, bool iscolumwrite)
10         {
11             int i = 0;
12             int j = 0;
13             int count = 0;
14             ISheet sheet = null;
15             using (fs = new FileStream(filepath, FileMode.OpenOrCreate, FileAccess.ReadWrite))
16             {
17                 //根据Excel不同版本实例不同工作铺
18                 if (filepath.IndexOf(".xlsx") > 0) // 2007版本
19                 {
20                     workbook = new XSSFWorkbook();
21                 }
22                 else if (filepath.IndexOf(".xls") > 0) // 2003版本
23                     workbook = new HSSFWorkbook();
24 
25                 try
26                 {
27                     if (workbook != null)
28                     {
29                         sheet = workbook.CreateSheet(sheename);
30                     }
31                     else
32                     {
33                         return -1;
34                     }
35 
36                     if (iscolumwrite == true) //写入DataTable的列名
37                     {
38                         IRow row = sheet.CreateRow(0);
39                         for (j = 0; j < data.Columns.Count; ++j)
40                         {
41                             row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
42                         }
43                         count = 1;
44                     }
45                     else
46                     {
47                         count = 0;
48                     }
49 
50                     for (i = 0; i < data.Rows.Count; ++i)
51                     {
52                         IRow row = sheet.CreateRow(count);
53                         for (j = 0; j < data.Columns.Count; ++j)
54                         {
55                             row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());
56                         }
57                         count++;
58                     }
59                     workbook.Write(fs); //写入到excel
60                     return count;
61                 }
62                 catch (Exception ex)
63                 {
64                     Console.WriteLine("Exception: " + ex.Message);
65                     return -1;
66                 }
67                 finally { fs.Close(); fs.Dispose(); }
68             }
69         }

 

 1       /// <summary>
 2         /// 将Excel导入DataTable
 3         /// </summary>
 4         /// <param name="filepath">导入的文件路径(包括文件名)</param>
 5         /// <param name="sheetname">工作表名称</param>
 6         /// <param name="isFirstRowColumn">第一行是否是DataTable的列名</param>
 7         /// <returns>DataTable</returns>
 8         public DataTable ExcelToDataTable(string filepath, string sheetname, bool isFirstRowColumn)
 9         {
10             ISheet sheet = null;//工作表
11             DataTable data = new DataTable();
12 
13             var startrow = 0;
14             using (fs = new FileStream(filepath, FileMode.Open, FileAccess.Read))
15             {
16                 try
17                 {
18                     if (filepath.IndexOf(".xlsx") > 0) // 2007版本
19                         workbook = new XSSFWorkbook(fs);
20                     else if (filepath.IndexOf(".xls") > 0) // 2003版本
21                         workbook = new HSSFWorkbook(fs);
22                     if (sheetname != null)
23                     {
24                         sheet = workbook.GetSheet(sheetname);
25                         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
26                         {
27                             sheet = workbook.GetSheetAt(0);
28                         }
29                     }
30                     else
31                     {
32                         sheet = workbook.GetSheetAt(0);
33                     }
34                     if (sheet != null)
35                     {
36                         IRow firstrow = sheet.GetRow(0);
37                         int cellCount = firstrow.LastCellNum; //行最后一个cell的编号 即总的列数
38                         if (isFirstRowColumn)
39                         {
40                             for (int i = firstrow.FirstCellNum; i < cellCount; i++)
41                             {
42                                 ICell cell = firstrow.GetCell(i);
43                                 if (cell != null)
44                                 {
45                                     string cellvalue = cell.StringCellValue;
46                                     if (cellvalue != null)
47                                     {
48                                         DataColumn column = new DataColumn(cellvalue);
49                                         data.Columns.Add(column);
50                                     }
51                                 }
52                             }
53                             startrow = sheet.FirstRowNum + 1;
54                         }
55                         else
56                         {
57                             startrow = sheet.FirstRowNum;
58                         }
59                         //读数据行
60                         int rowcount = sheet.LastRowNum;
61                         for (int i = startrow; i < rowcount; i++)
62                         {
63                             IRow row = sheet.GetRow(i);
64                             if (row == null)
65                             {
66                                 continue; //没有数据的行默认是null
67                             }
68                             DataRow datarow = data.NewRow();//具有相同架构的行
69                             for (int j = row.FirstCellNum; j < cellCount; j++)
70                             {
71                                 if (row.GetCell(j) != null)
72                                 {
73                                     datarow[j] = row.GetCell(j).ToString();
74                                 }
75                             }
76                             data.Rows.Add(datarow);
77                         }
78                     }
79                     return data;
80                 }
81                 catch (Exception ex)
82                 {
83                     Console.WriteLine("Exception: " + ex.Message);
84                     return null;
85                 }
86                 finally { fs.Close(); fs.Dispose(); }
87             }
88         }

 

测试代码:

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Data;
 6 
 7 using NPOIHelperTool;
 8 using Bll;
 9 namespace ConsoleApplication1
10 {
11     class Program
12     {
13         static void Main(string[] args)
14         {
15             DataTable data = new DataTable();
16             for (int i = 0; i < 5; ++i)
17             {
18                 data.Columns.Add("Columns_" + i.ToString(), typeof(string));
19             }
20 
21             for (int i = 0; i < 10; ++i)
22             {
23                 DataRow row = data.NewRow();
24                 row["Columns_0"] = "item0_" + i.ToString();
25                 row["Columns_1"] = "item1_" + i.ToString();
26                 row["Columns_2"] = "item2_" + i.ToString();
27                 row["Columns_3"] = "item3_" + i.ToString();
28                 row["Columns_4"] = "item4_" + i.ToString();
29                 data.Rows.Add(row);
30             }
31 
32             ExcelHelper h = new ExcelHelper();
33             DataTable de = h.ExcelToDataTable(@"E:\Myuser.xls", "Sheet1", true);
34             int c = h.DataTableToExcel(data, @"E:\Test.xls", "sheet1", true);
35             IList<student> a = TypeUtil.ToList<student>(de);
36         }
37 
38     }
39     class student
40     {
41         public string Id { get; set; }
42         public string Name { get; set; }
43         public string nc { get; set; }
44     }
45 }
View Code

 

参考:

https://www.cnblogs.com/Raning/p/5872822.html

https://blog.csdn.net/dcrmg/article/details/52356236

http://www.cnblogs.com/Erik_Xu/archive/2012/06/08/2541957.html

 

作者:遥远的Ta

出处:https://www.cnblogs.com/lycb

posted @ 2019-04-25 23:09  遥远的Ta  阅读(7561)  评论(0编辑  收藏  举报