NPOI excel导入模板

public List ImportExe()
{
try
{
OpenFileDialog ofd = new OpenFileDialog();
ofd.Title = "Excel文件"; ofd.FileName = "";
ofd.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
ofd.Filter = "所有文件(.)|.|Excel2003文件(.xls)|.xls|Excel2007文件(.xlsx)|.xlsx";
ofd.ValidateNames = true;
ofd.CheckFileExists = true;
ofd.CheckPathExists = true;
string file = string.Empty;
if (ofd.ShowDialog() == DialogResult.OK)
{ file = ofd.FileName; }
if (file == "")
{ XtraMessageBox.Show("没有选择Excel文件！无法进行数据导入"); }
else
{
List dataList = new List();
IWorkbook workbook;
string fileExt = Path.GetExtension(file).ToLower();
using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read))
{
//根据不同版本
if (fileExt == ".xlsx")//2007版本
{
workbook = new XSSFWorkbook(fs);
}
else if (fileExt == ".xls")//2003版本
{
workbook = new HSSFWorkbook(fs);
}
else
{
workbook = null;
}
//获取第一个sheet页内容
ISheet sheet = workbook.GetSheetAt(0);
int count = workbook.NumberOfSheets;//获取sheet页总数量
for (int z = 0; z < count; z++)
{
DataTable dt = new DataTable();
dt.TableName = sheet.SheetName;
sheet = workbook.GetSheetAt(z);
//表头
IRow header = sheet.GetRow(sheet.FirstRowNum);
if (header == null) continue;
List columns = new List();
for (int i = 0; i < header.LastCellNum; i++)
{
columns.Add(i);
ICell a = header.GetCell(i);//列名
DataColumn dc = new DataColumn(a.ToString(), typeof(string));
dt.Columns.Add(dc);
}
//数据值
for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum - 1; i++)
{
DataRow dr = dt.NewRow();
foreach (int j in columns)
{
if (sheet.GetRow(i) != null)
dr[j] = sheet.GetRow(i).GetCell(j);
}
dt.Rows.Add(dr);
}
List list = ConvertViewModel(dt);
if (list == null)
{
XtraMessageBox.Show("没有导入的数据，请检查表格里的数据格式是否正确");
return null;
}
return list;
}
}
}
return null;
}
catch (Exception ex)
{
XtraMessageBox.Show($"{ex}");
return null;
}
}

    public List<T> ConvertViewModel(DataTable dt)
    {
        List<T> items = new List<T>();
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            if (dt.Rows[i]["题型"] == null || dt.Rows[i]["题目内容"] == null || dt.Rows[i]["答案"] == null)
            {
                XtraMessageBox.Show("题型或者题目内容或者答案不能为空");
                return null;
            }
            T item = new T();
            item.answer = dt.Rows[i]["答案"].ToString().Trim();
            item.option1 = dt.Rows[i]["选项1"].ToString().Trim();
            item.option2 = dt.Rows[i]["选项2"].ToString().Trim();
            item.option3 = dt.Rows[i]["选项3"].ToString().Trim();
            item.option4 = dt.Rows[i]["选项4"].ToString().Trim();
            item.option5 = dt.Rows[i]["选项5"].ToString().Trim();
            item.question_content = dt.Rows[i]["题目内容"].ToString().Trim()?.Replace("_____","(   )");
            item.question_type = GetQuestiontype(dt.Rows[i]["题型"].ToString().Trim());
            items.Add(item);
        }
        return items;
    }