Question

I have 15 comboBox’es, and I do not want to create an event handler for each. How do I make just one procedure and tie all Combobox’es to it?

private void cbSlots0_SelectedIndexChanged(object sender, EventArgs e)
{
    var item = ConfigClass.Slots["0"][cbSlots0.SelectedIndex];
    ConfigClass.Slots["0"].Insert(0, item);
    ConfigClass.Slots["0"].RemoveAt(cbSlots0.SelectedIndex + 1);
}

private void cbSlots1_SelectedIndexChanged(object sender, EventArgs e)
{
    var item = ConfigClass.Slots["1"][cbSlots1.SelectedIndex];
    ConfigClass.Slots["1"].Insert(1, item);
    ConfigClass.Slots["1"].RemoveAt(cbSlots1.SelectedIndex + 1);
}

Correct answer:

var cb = ((ComboBox)sender);
            var tag = int.Parse(cb.Tag.ToString());
            var item = ConfigClass.Slots[tag.ToString()][cb.SelectedIndex];
            ConfigClass.Slots[tag.ToString()].Insert(tag, item);
            ConfigClass.Slots[tag.ToString()].RemoveAt(cb.SelectedIndex + 1);

Answer 1

You can give each ComboBox a distinct Tag, which contains the number of the entry in the ConfigClass, and then use that like so:

private void cbSlots0_SelectedIndexChanged(object sender, EventArgs e)
{
    int tag = (int)((ComboBox)sender).Tag;
    var item = ConfigClass.Slots[tag.ToString()][cbSlots0.SelectedIndex];
    ConfigClass.Slots[tag.ToString()].Insert(tag, item);
    ConfigClass.Slots[tag.ToString()].RemoveAt(cbSlots0.SelectedIndex + 1);
}

The tag can contain any data you want, so if you need something more complex stored in there, that’s also a possibility.