comboBox1.ValueMember = "Item1";
            label1.DataBindings.Add(new Binding("Text",
                comboBox1.DataSource = new BindingSource() 
		{ DataSource = new List<Tuple<int, string>> { Tuple.Create(1212, "Текст12"), Tuple.Create(1313, "Текст13") } },
                "Item2")
            );

comboBox1.ValueMember = "key";
label1.DataBindings.Add(new Binding("Text", comboBox1.DataSource = new BindingSource() { DataSource = new Dictionary<int,string>() { { 1212, "Текст12" }, { 1213, "Текст13" } } }, "value"));