Messing with listbox collections and random fun

Some who may remember a couple of posts from me ages ago will know I am a complete part-time noob (!)

I am getting somewhere with my 'game'. Now I am just kind of cleaning things up and other bits to take my mind off the main program workings for a little bit (my head hurts...)

Right now, I have four combo boxes on my form and the items in the collection are built in another section of code (specifically, the end turn button) which you can see below:

Code:

---

for(int loop = 0 ; loop <= 3 ; loop++)
{
        ((ComboBox)ActionNameComboBoxes[loop]).Items.Clear();
}
if(tech[0,24] > 0 && tech[0,13] > 0)
{
        for(int sohg = 0; sohg <= tech[0,24]-1; sohg++)
        {
                ((ComboBox)ActionNameComboBoxes[sohg]).Enabled = true;
                for(int sohg2 = 13; sohg2 <= tech[0,13]+12; sohg2++)
                {
                        ((ComboBox)ordercomboboxes[sohg]).Items.Add(sohg2.ToString());
                }
        }
}

---

Now the fun part is fiddling with these collections each time a user changes the selection in one combo box. Something like, in the first box, the user selects 13 from a selection of 13 to 18. The other boxes are now modified to remove 13 from their collections like so:

Code:

---

public void OLActionBox_SelectedIndexChanged(object sender, System.EventArgs e)
{
        for(int sohg2 = 13; sohg2 <= tech[0,24]+12; sohg2++)
        {
                if(((System.Windows.Forms.ComboBox)sender).Name != ((ComboBox)ordercomboboxes[sohg2-13]).Name)
                {
((ComboBox)ordercomboboxes[sohg2-13]).Items.Remove((string)((System.Windows.Forms.ComboBox)sender).SelectedItem);
                }
        }
}

---

I am wanting to deal with a user that is spelt with an L at the beginning. Ie, the user selects 13, 14, 15, 16 respectively in each box, but then decides to change his 13 selection to 17. I am struggling on adding 13 back in to each combobox selection! What is the best way of doing this? No need to do it for me, just give a way of doing it, that I can work on.

And now for the random numbers. I hate random numbers. How can I generate in a loop 12 different numbers, but all in the range of 0 to 11?

Code:

---

for( loop = 0 ; loop <= 11 ; loop++)
{
        array[loop] = rnd.Next(0,11)
}

---

Thats what I can figure out, except the program hangs in this loop.