npoi读取excel：
1.导入excel为datatable类型：
private void button1_Click(object sender, EventArgs e)
{
OpenFileDialog dialog = new OpenFileDialog();
dialog.Multiselect = true;//该值确定是否可以选择多个文件
dialog.Title = "请选择文件夹";
dialog.Filter = "所有文件(*.*)|*.*";
if (dialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
string file = dialog.FileName;
DataTable dt = ExcelToDataTable(file, false);
}
}
/// <summary>
/// 将excel导入到datatable
/// </summary>
/// <param name="filePath">excel路径</param>
/// <param name="isColumnName">第一行是否是列名</param>
/// <returns>返回datatable</returns>
public DataTable ExcelToDataTable(string filePath, bool isColumnName)
{
DataTable dataTable = null;
FileStream fs = null;
DataColumn column = null;
DataRow dataRow = null;
IWorkbook workbook = null;
ISheet sheet = null;
IRow row = null;
ICell cell = null;
int startRow = 0;
try
{
using (fs = File.OpenRead(filePath))
{
// 2007版本
if (filePath.IndexOf(".xlsx") > 0)
workbook = new XSSFWorkbook(fs);
// 2003版本
else if (filePath.IndexOf(".xls") > 0)
workbook = new HSSFWorkbook(fs);
if (workbook != null)
{
sheet = workbook.GetSheetAt(0);//读取第一个sheet，当然也可以循环读取每个sheet
dataTable = new DataTable();
if (sheet != null)
{
int rowCount = sheet.LastRowNum;//总行数
if (rowCount > 0)
{
IRow firstRow = sheet.GetRow(0);//第一行
int cellCount = firstRow.LastCellNum;//列数
//构建datatable的列
if (isColumnName)
{
startRow = 1;//如果第一行是列名，则从第二行开始读取
for (int i = firstRow.FirstCellNum; i < cellCount; i++)
{
cell = firstRow.GetCell(i);
if (cell != null)
{
//if (cell.StringCellValue != null)
if (cell.StringCellValue != null)
{
column = new DataColumn(cell.StringCellValue);
dataTable.Columns.Add(column);
}
}
}
}
else
{
for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
{
column = new DataColumn("column" + (i + 1));
dataTable.Columns.Add(column);
}
}
//填充行
for (int i = startRow; i <= rowCount; ++i)
{
row = sheet.GetRow(i);
if (row == null) continue;
dataRow = dataTable.NewRow();
for (int j = row.FirstCellNum; j < cellCount; ++j)
{
cell = row.GetCell(j);
if (cell == null)
{
dataRow[j] = "";
}
else
{
switch (cell.CellType)
{
case CellType.Blank:
dataRow[j] = "";
break;
case CellType.Numeric:
short format = cell.CellStyle.DataFormat;
//对时间格式
if (format == 14 || format == 31 || format == 57 || format == 58)
dataRow[j] = cell.DateCellValue;
else
dataRow[j] = cell.NumericCellValue;
break;
case CellType.String:
dataRow[j] = cell.StringCellValue;
break;
}
}
}
dataTable.Rows.Add(dataRow);
}
}
}
}
}
return dataTable;
}
catch (Exception)
{
if (fs != null)
{
fs.Close();
}
return null;
}
}
来源：https://blog.csdn.net/Luna0923/article/details/100860134