DataGridView数据用NPOI导出到Excel

/// <summary>
/// DataGridView数据用NPOI导出到Excel
/// </summary>
/// <param name="fileName">Excel文件名</param>
/// <param name="dgv">DataGridView数据</param>
public static void GridToExcel(string fileName, DataGridView dgv)
{
if (dgv.Rows.Count == 0)
{
return;
}
SaveFileDialog sfd = new SaveFileDialog();
sfd.Filter = "Excel 2003格式|*.xls";
sfd.FileName = fileName + DateTime.Now.ToString("yyyyMMddHHmmssms");
if (sfd.ShowDialog() != DialogResult.OK)
{
return;
}
HSSFWorkbook wb = new HSSFWorkbook();
ISheet sheet = wb.CreateSheet(fileName);
IRow headRow = sheet.CreateRow(0);
for (int i = 0; i < dgv.Columns.Count; i++)
{
headRow.CreateCell(i).SetCellValue(dgv.Columns[i].HeaderText);
}
for (int i = 0; i < dgv.Rows.Count; i++)
{
IRow row = sheet.CreateRow(i + 1);
for (int j = 0; j < dgv.Columns.Count; j++)
{
ICell cell = row.CreateCell(j);
if (dgv.Rows[i].Cells[j].Value == DBNull.Value)
{
cell.SetCellType(CellType.Blank);
}
else
{
if (dgv.Rows[i].Cells[j].ValueType.FullName.Contains("System.Int32"))
{
cell.SetCellValue(Convert.ToInt32(dgv.Rows[i].Cells[j].Value));
}
else if (dgv.Rows[i].Cells[j].ValueType.FullName.Contains("System.String"))
{
cell.SetCellValue(dgv.Rows[i].Cells[j].Value.ToString());
}
else if (dgv.Rows[i].Cells[j].ValueType.FullName.Contains("System.Single"))
{
cell.SetCellValue(Convert.ToSingle(dgv.Rows[i].Cells[j].Value));
}
else if (dgv.Rows[i].Cells[j].ValueType.FullName.Contains("System.Double"))
{
cell.SetCellValue(Convert.ToDouble(dgv.Rows[i].Cells[j].Value));
}
else if (dgv.Rows[i].Cells[j].ValueType.FullName.Contains("System.Decimal"))
{
cell.SetCellValue(Convert.ToDouble(dgv.Rows[i].Cells[j].Value));
}
else if (dgv.Rows[i].Cells[j].ValueType.FullName.Contains("System.DateTime"))
{
cell.SetCellValue(Convert.ToDateTime(dgv.Rows[i].Cells[j].Value).ToString("yyyy-MM-dd"));
}
}
}

}
for (int i = 0; i < dgv.Columns.Count; i++)
{
sheet.AutoSizeColumn(i);//自动列宽

}
using (FileStream fs = new FileStream(sfd.FileName, FileMode.Create))
{
wb.Write(fs);
}
//成功提示
if (MessageBox.Show("导出成功，是否立即打开？", "提示", MessageBoxButtons.YesNo, MessageBoxIcon.Information) == DialogResult.Yes)
{
System.Diagnostics.Process.Start(sfd.FileName);
}

}