CODE: Select All private void Form1_Load(object sender, EventArgs e) { List<MonAn> thucDon = new List<MonAn>(); thucDon.Add(new MonAn("Ga Ran KFC", 150000, 120000)); thucDon.Add(new MonAn("Vit Quay", 130000, 110000)); thucDon.Add(new MonAn("Tom Ran", 80000, 60000)); cbtinh.DataSource = thucDon; } class MonAn { public string Name; public List<int> gia; public MonAn(String ten, int a, int b) { Name = ten; gia = new List<int>(); gia.Add(a); gia.Add(b); } public override string ToString() { return Name; } } private void cbtinh_SelectedIndexChanged(object sender, EventArgs e) { if (cbtinh.SelectedValue != null) { cb2.DataSource = (cbtinh.SelectedValue as MonAn).gia; } }