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个人比较习惯用NPOI操作excel，方便易理解。在宇宙第一IDE（笑）——VS2017中插入NPOI就很方便：
首先安装NPOI：
然后在.cs文件中加入如下引用：
using NPOI.SS.UserModel; using NPOI.XSSF.UserModel; using NPOI.HSSF.UserModel;
XSSF是用于.xlsx（2007以后版本）
HSSF是用于.xls（2007以前版本）
同时我的代码中要用到Datatable，用于存储表格数据
读写文件需要IO
using System.Data; using System.IO
接下来是读写excel的代码：
首先从excel中读入数据存入datatable并返回：
/// <summary> /// Excel导入成DataTble /// </summary> /// <param name="file">导入路径(包含文件名与扩展名)</param> /// <returns></returns> public static DataTable ExcelToTable(string file) { DataTable dt = new DataTable(); IWorkbook workbook; string fileExt = Path.GetExtension(file).ToLower(); using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read)) { if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(fs); } else if (fileExt == ".xls") { workbook = new HSSFWorkbook(fs); } else { workbook = null; } if (workbook == null) { return null; } ISheet sheet = workbook.GetSheetAt(0); //表头 IRow header = sheet.GetRow(sheet.FirstRowNum); List<int> columns = new List<int>(); for (int i = 0; i < header.LastCellNum; i++) { object obj = GetValueType(header.GetCell(i)); if (obj == null || obj.ToString() == string.Empty) { dt.Columns.Add(new DataColumn("Columns" + i.ToString())); } else dt.Columns.Add(new DataColumn(obj.ToString())); columns.Add(i); } //数据 for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum; i++) { DataRow dr = dt.NewRow(); bool hasValue = false; foreach (int j in columns) { dr[j] = GetValueType(sheet.GetRow(i).GetCell(j)); if (dr[j] != null && dr[j].ToString() != string.Empty) { hasValue = true; } } if (hasValue) { dt.Rows.Add(dr); } } } return dt; }
同时支持.xlsx和.xls
上面代码用到了GetValueType函数：
/// <summary> /// 获取单元格类型 /// </summary> /// <param name="cell">目标单元格</param> /// <returns></returns> private static object GetValueType(ICell cell) { if (cell == null) return null; switch (cell.CellType) { case CellType.Blank: return null; case CellType.Boolean: return cell.BooleanCellValue; case CellType.Numeric: return cell.NumericCellValue; case CellType.String: return cell.StringCellValue; case CellType.Error: return cell.ErrorCellValue; case CellType.Formula: default: return "=" + cell.CellFormula; } }
最后是datatable写入excel（仅适用于.xlsx）文件：
/// <summary> /// Datable导出成Excel(xlsx) /// </summary> /// <param name="dt"></param> /// <param name="file">导出路径(包括文件名与扩展名)</param> public static void TableToExcel(DataTable dt, string file) { IWorkbook workbook; string fileExt = Path.GetExtension(file).ToLower();if (workbook == null) { return; } ISheet sheet = string.IsNullOrEmpty(dt.TableName) ? workbook.CreateSheet("sheet0") : workbook.CreateSheet(dt.TableName); //表头 IRow row = sheet.CreateRow(0); for (int i = 0; i < dt.Columns.Count; i++) { ICell cell = row.CreateCell(i); cell.SetCellValue(dt.Columns[i].ColumnName); } //数据 for (int i = 0; i < dt.Rows.Count; i++) { IRow row1 = sheet.CreateRow(i + 1); for (int j = 0; j < dt.Columns.Count; j++) { ICell cell = row1.CreateCell(j);
cell.SetCellValue(dt.Rows[i][j].ToString());
} } //转为字节数组 MemoryStream stream = new MemoryStream(); workbook.Write(stream); var buf = stream.ToArray(); //保存为Excel文件
using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Write)) { fs.Write(buf, 0, buf.Length); fs.Flush(); } }
其中:
using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Write))
这一行，FileMode.open会在已有的文件中加入你所create的sheet，适用FileMode.create会创新新文件，几遍已有文件，也会删掉该文件。
这是写入.xls文件的代码
/// <summary> /// 将datatable写入到excel(xls) /// </summary> /// <param name="dt">datatable</param> /// <param name="filepath">写入的文件路径</param> /// <returns></returns> public static bool DataTableToExcel(DataTable dt, string filepath) { bool result = false; IWorkbook workbook = null; FileStream fs = null; IRow row = null; ISheet sheet = null; ICell cell = null; try { if (dt != null && dt.Rows.Count > 0) { workbook = new HSSFWorkbook(); sheet = workbook.CreateSheet("Sheet0");//创建一个名称为Sheet0的表 int rowCount = dt.Rows.Count;//行数 int columnCount = dt.Columns.Count;//列数 int cellnum; //设置列头 row = sheet.CreateRow(0);//excel第一行设为列头 for (int c = 0; c < columnCount; c++) { cell = row.CreateCell(c); cell.SetCellValue(dt.Columns[c].ColumnName); } //设置每行每列的单元格, for (int i = 0; i < rowCount; i++) { row = sheet.CreateRow(i + 1); for (int j = 0; j < columnCount; j++) { cell = row.CreateCell(j);//excel第二行开始写入数据 //cell.SetCellValue(dt.Rows[i][j].ToString()); //保存单元格格式为数字 if (j < 2) { cell.SetCellValue(dt.Rows[i][j].ToString()); } else { //cell.SetCellValue(int.Parse(dt.Rows[i][j].ToString())); if (dt.Rows[i][j] is DBNull) { cell.SetCellValue(dt.Rows[i][j].ToString()); } else { cellnum = Convert.ToInt32(dt.Rows[i][j].ToString()); cell.SetCellValue(cellnum); } } } } if (System.IO.File.Exists(filepath)) { if (MessageBox.Show("该文件已存在！确定覆盖吗？", "WARNING", MessageBoxButtons.OKCancel) == DialogResult.OK) { File.Delete(filepath); } else { return false; } } using (fs = File.OpenWrite(filepath)) { workbook.Write(fs);//向打开的这个xls文件中写入数据 result = true; } } return result; } catch (Exception ex) { MessageBox.Show(ex.Message); if (fs != null) { fs.Close(); } return false; } }
最后，虽然不常用，但是关键时刻很有用的，写入文件时设置每个单元格数据类型的代码：
/// <summary> /// 设置单元格数据类型 /// </summary> /// <param name="cell">目标单元格</param> /// <param name="obj">数据值</param> /// <returns></returns> public static void SetCellValue(ICell cell, object obj) { if (obj.GetType() == typeof(int)) { cell.SetCellValue((int)obj); } else if (obj.GetType() == typeof(double)) { cell.SetCellValue((double)obj); } else if (obj.GetType() == typeof(IRichTextString)) { cell.SetCellValue((IRichTextString)obj); } else if (obj.GetType() == typeof(string)) { cell.SetCellValue(obj.ToString()); } else if (obj.GetType() == typeof(DateTime)) { cell.SetCellValue((DateTime)obj); } else if (obj.GetType() == typeof(bool)) { cell.SetCellValue((bool)obj); } else { cell.SetCellValue(obj.ToString()); } }