public void ChooseQuestionsForTest()
{
while (QuestionsRandomlyChoosenForTest.Count < NumberOfQuestionsForThisTest)
{
Random r = new Random();
int _question = r.Next(QuestionsInSet.Count);
if (!QuestionsRandomlyChoosenForTest.Contains(QuestionsInSet[_question]))
{
QuestionsRandomlyChoosenForTest.Add(QuestionsInSet[_question]);
}
}
}