How to select auto-complete text box items using arrow keys in c#

Question

This is my code for setting source for auto-complete text box it works perfectly. But I want to know how to select the items using arrow keys. Please help me..

public void GetSource()
        {
            List<string> listnew= prolg.GetSource();
            var listn = new AutoCompleteStringCollection();
            listn.AddRange(listnew.ToArray());
            txt_category.AutoCompleteCustomSource = listn;
        }