private void btnExportQuestion_Click(object sender, EventArgs e)
{
List <Question> lst = new List <Question>();
using (var db = new dbQLThiTracNghiemDataContext())
{
lst = db.Questions.ToList();
}
myExcel.Export(MyTool.ConvertToDataTable(lst));
MessageBox.Show("Xuất câu hỏi thành công!");
}