The process of adding dataitems itself is wrong.
While inserting, do this:
comboBox1.Items.Insert(0,new ListItem("1 Second","1");
comboBox1.Items.Insert(1,new ListItem("2 Second","2");
This way you can easily fetch corresponding values for selected items:
textBox1.Text= comboBox1.SelectedItem.Value;
Hope this helps.
(I haven't checked the code on code editor, so may contain syntactical errors, otherwise logic will always be the same)
Anurag :rose: