NPOI帮助类

深藏阁楼爱情的钟 2021-06-26 16:06 436阅读 0赞

## ExcelHelper.cs ##

using System;
    using System.Data;
    using System.IO;
    using NPOI.HSSF.UserModel;
    using NPOI.SS.UserModel;
    using NPOI.XSSF.UserModel;
    
    namespace BaiduMap
    {
        public class ExcelHelper
        {
            private bool disposed;
            private readonly string fileName; //文件名
            private FileStream fs;
            private IWorkbook workbook;
    
            public ExcelHelper(string fileName)
            {
                this.fileName = fileName;
                disposed = false;
            }
    
            /// <summary>
            /// 将DataTable数据导入到excel中
            /// </summary>
            /// <param name="data">要导入的数据</param>
            /// <param name="isColumnWritten">DataTable的列名是否要导入</param>
            /// <param name="sheetName">要导入的excel的sheet的名称</param>
            /// <returns>导入数据行数(包含列名那一行)</returns>
            public int DataTableToExcel(DataTable data, string sheetName, bool isColumnWritten)
            {
                var i = 0;
                var j = 0;
                var count = 0;
                ISheet sheet = null;
    
                fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
                if (fileName.IndexOf(".xlsx") > 0) // 2007版本
                    workbook = new XSSFWorkbook();
                else if (fileName.IndexOf(".xls") > 0) // 2003版本
                    workbook = new HSSFWorkbook();
    
                try
                {
                    if (workbook != null)
                    {
                        sheet = workbook.CreateSheet(sheetName);
                    }
                    else
                    {
                        return -1;
                    }
    
                    if (isColumnWritten) //写入DataTable的列名
                    {
                        var row = sheet.CreateRow(0);
                        for (j = 0; j < data.Columns.Count; ++j)
                        {
                            row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
                        }
                        count = 1;
                    }
                    else
                    {
                        count = 0;
                    }
    
                    for (i = 0; i < data.Rows.Count; ++i)
                    {
                        var row = sheet.CreateRow(count);
                        for (j = 0; j < data.Columns.Count; ++j)
                        {
                            row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());
                        }
                        ++count;
                    }
                    workbook.Write(fs); //写入到excel
                    return count;
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Exception: " + ex.Message);
                    return -1;
                }
            }
    
            /// <summary>
            /// 将excel中的数据导入到DataTable中
            /// </summary>
            /// <param name="sheetName">excel工作薄sheet的名称</param>
            /// <param name="isFirstRowColumn">第一行是否是DataTable的列名</param>
            /// <returns>返回的DataTable</returns>
            public DataTable ExcelToDataTable(string sheetName, bool isFirstRowColumn)
            {
                ISheet sheet = null;
                var data = new DataTable();
                var startRow = 0;
                try
                {
                    fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
                    if (fileName.IndexOf(".xlsx") > 0) // 2007版本
                        workbook = new XSSFWorkbook(fs);
                    else if (fileName.IndexOf(".xls") > 0) // 2003版本
                        workbook = new HSSFWorkbook(fs);
    
                    if (sheetName != null)
                    {
                        sheet = workbook.GetSheet(sheetName);
                        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
                        {
                            sheet = workbook.GetSheetAt(0);
                        }
                    }
                    else
                    {
                        sheet = workbook.GetSheetAt(0);
                    }
                    if (sheet != null)
                    {
                        var firstRow = sheet.GetRow(0);
                        int cellCount = firstRow.LastCellNum; //一行最后一个cell的编号 即总的列数
    
                        if (isFirstRowColumn)
                        {
                            for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                            {
                                var cell = firstRow.GetCell(i);
                                if (cell != null)
                                {
                                    cell.SetCellType(CellType.String);
                                    var cellValue = cell.StringCellValue;
                                    if (!string.IsNullOrEmpty(cellValue))
                                    {
                                        var column = new DataColumn(cellValue);
                                        data.Columns.Add(column);
                                    }
                                }
                            }
                            startRow = sheet.FirstRowNum + 1;
                        }
                        else
                        {
                            //生成列
                            for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                            {
                                var column = new DataColumn("列"+i);
                                data.Columns.Add(column);
                            }
                            startRow = sheet.FirstRowNum;
                        }
    
                        //最后一列的标号
                        var rowCount = sheet.LastRowNum;
                        for (var i = startRow; i <= rowCount; ++i)
                        {
                            var row = sheet.GetRow(i);
                            if (row == null) continue; //没有数据的行默认是null　　　　　　　
    
                            var dataRow = data.NewRow();
                            for (int j = row.FirstCellNum; j < cellCount; ++j)
                            {
                                if (row.GetCell(j) != null) //同理，没有数据的单元格都默认是null
                                    dataRow[j] = row.GetCell(j).ToString();
                            }
                            data.Rows.Add(dataRow);
                        }
                    }
    
                    return data;
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Exception: " + ex.Message);
                    return null;
                }
            }
    
            public void Dispose()
            {
                Dispose(true);
                GC.SuppressFinalize(this);
            }
    
            protected virtual void Dispose(bool disposing)
            {
                if (!disposed)
                {
                    if (disposing)
                    {
                        if (fs != null)
                            fs.Close();
                    }
    
                    fs = null;
                    disposed = true;
                }
            }
        }
    }

## 使用 ##

var filePath=Environment.CurrentDirectory + "\\test.xlsx"
     var dt = new DataTable();
     dt= new ExcelHelper(filePath).ExcelToDataTable("test", false);