How to set valueMember for combobox items C#

I had to find out how to set values into ComboBox items

So i have a combo box with two string items and each item make some changes on other combo box then save to xml

Now i tried to set value for this items but the problem is the xml output shows only 1 value

comReg.DisplayMember = "Item 1";
comReg.ValueMember = "1";
comReg.DisplayMember = "Item 2";
comReg.ValueMember = "2";
comPer.Items.Clear();
switch (comReg.SelectedItem.ToString()) {
case "Item 1":
comPer.Items.AddRange(new string[]{"1", "2", "3", "4" });
break;
case "Item 2":
comPer.Items.AddRange(new string[]{"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12"});
break;