こんなんです
MyCard Card1 = new MyCard(rnd.Next(1, 13), rnd.Next(1, 4));
MyCard Card2 = new MyCard(rnd.Next(1, 13), rnd.Next(1, 4));
MyCard Card3 = new MyCard(rnd.Next(1, 13), rnd.Next(1, 4));
略
lblNo1.Text = Card1.myno.ToString();
lblNo2.Text = Card2.myno.ToString();
lblNo3.Text = Card3.myno.ToString();

略

lblMark1.Text = Card1.mymark.ToString();

lblMark2.Text = Card2.mymark.ToString();

lblMark3.Text = Card3.mymark.ToString();
略
ださいでしょ
なんとかならんのか