private void SelectQuestionForm_Load(object sender, EventArgs e)
        {
            dataset = ds;
            dataset.QuestionsEx.Clear();
            dbObject.GetAllQuestionsEx(dataset);
            int count = 0;

            for (int i = 0; i < dataset.QuestionsEx.Count; ++i)
            {
                if (dataset.QuestionsEx[i].SetId == setId)
                {
                    dataset.QuestionsEx[i].Delete();
                    count++;
                    continue;
                }
                if (!dataset.QuestionSetsEx.FindById(setId).IsQuestionTypeIdNull())
                {
                    if (dataset.QuestionsEx[i].TypeId != dataset.QuestionSetsEx.FindById(setId).QuestionTypeId)
                    {
                        dataset.QuestionsEx[i].Delete();
                        count++;
                        continue;
                    }
                }
            }
            if (count == dataset.QuestionsEx.Count)
            {
                MessageBox.Show("Not valid to add question in database.", "Select question", MessageBoxButtons.OK,
                                MessageBoxIcon.Warning);
                {
                    DialogResult = DialogResult.Cancel;
                }
            }
            questionDataGrid.DataSource  = dataset;
            type.DataSource              = dataset;
            subType.DataSource           = dataset;
            difficultyLevelId.DataSource = dataset;
            questionDataGrid.Update();
        }