First I set the modifier property to "Internal" of comboBox1 on form1.
I used the following code:
form1 f1 = new form1();
object[] obj = new object[f1.comboBox1.Items.Count];
f1.comboBox.Items.CopyTo(obj, 0);
comboBox2.Items.AddRange(obj);`
Is it the best way to do this?
PS: I couldn't make this: Best way to access a control on another form in Windows Forms? to work.
PPS: Making controls is public is not what I like and neither preferred.