C#对Execl操作类

1.NuGet下安装 NPOI

2.实例代码：（可以根据具体情况注释和添加代码逻辑）

public class ExeclHelper
{
/// <summary>
/// 将excel文件内容读取到DataTable数据表中
/// </summary>
/// <param name="fileName">文件完整路径名</param>
/// <param name="sheetName">指定读取excel工作薄sheet的名称</param>
/// <param name="isFirstRowColumn">第一行是否是DataTable的列名：true=是，false=否</param>
/// <returns>DataTable数据表</returns>
public static DataTable ReadExcelToDataTable(string fileName, List<string> cellList, string sheetName = "Sheet", bool isFirstRowColumn = true)
{
if (!File.Exists(fileName))
{
if(!TableToExcel(new DataTable(), fileName, cellList))
return null;
}
//定义要返回的datatable对象
DataTable data = new DataTable();
//excel工作表
NPOI.SS.UserModel.ISheet sheet = null;
//数据开始行(排除标题行)
int startRow = 0;
try
{
if (!File.Exists(fileName))
{
return null;
}
//根据指定路径读取文件
FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
//根据文件流创建excel数据结构
//NPOI.SS.UserModel.IWorkbook workbook = NPOI.SS.UserModel.WorkbookFactory.Create(fs);
//IWorkbook workbook = new HSSFWorkbook(fs);
IWorkbook workbook;
string fileExt = Path.GetExtension(fileName).ToLower();
if (fileExt == ".xlsx")
{
workbook = new XSSFWorkbook(fs);
}
else if (fileExt == ".xls")
{
workbook = new HSSFWorkbook(fs);
}
else
{
workbook = null;
}

if (workbook == null)
{
return new DataTable();
}
//如果有指定工作表名称
if (!string.IsNullOrEmpty(sheetName))
{
sheet = workbook.GetSheet(sheetName);
//如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
if (sheet == null)
{
sheet = workbook.GetSheetAt(0);
}
}
else
{
//如果没有指定的sheetName，则尝试获取第一个sheet
sheet = workbook.GetSheetAt(0);
}
if (sheet != null)
{
NPOI.SS.UserModel.IRow firstRow = sheet.GetRow(0);
//一行最后一个cell的编号 即总的列数
int cellCount = firstRow.LastCellNum;
//如果第一行是标题列名
if (isFirstRowColumn)
{
for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
{
NPOI.SS.UserModel.ICell cell = firstRow.GetCell(i);
if (cell != null)
{
string cellValue = cell.StringCellValue;
if (cellValue != null)
{
DataColumn column = new DataColumn(cellValue);
data.Columns.Add(column);
}
}
}
startRow = sheet.FirstRowNum + 1;
}
else
{
startRow = sheet.FirstRowNum;
}
//最后一列的标号
int rowCount = sheet.LastRowNum;
for (int i = startRow; i <= rowCount; ++i)
{
NPOI.SS.UserModel.IRow row = sheet.GetRow(i);
if (row == null) continue; //没有数据的行默认是null　　　　　　　

DataRow 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)
{
return null;
}
}

/// <summary>
/// Datable导出成Excel
/// </summary>
/// <param name="dt"></param>
/// <param name="file">导出路径(包括文件名与扩展名)</param>
public static bool TableToExcel(DataTable dt, string file,List<string> cellList)
{
try
{
//存在删除
if (File.Exists(file))
File.Delete(file);
IWorkbook workbook;
string fileExt = Path.GetExtension(file).ToLower();
if (fileExt == ".xlsx")
{
workbook = new XSSFWorkbook();
}
else if (fileExt == ".xls")
{
workbook = new HSSFWorkbook();
}
else
{
workbook = null;
return false;
}
ISheet sheet = workbook.CreateSheet("Sheet");

//表头
IRow row = sheet.CreateRow(0);
for (int i = 0; i < cellList.Count; i++)
{
ICell cell = row.CreateCell(i);
cell.SetCellValue(cellList[i]);
}

//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.Create, FileAccess.Write))
{
fs.Write(buf, 0, buf.Length);
fs.Flush();
}

return true;
}
catch(Exception ex)
{
return false;
}
}
}

注：cellList为execl表头集合