moel@392: 
moel@392: namespace OxyPlot.WindowsForms {
moel@392:   using System;
moel@392:   using System.Collections.Generic;
moel@392:   using System.Text;
moel@392: 
moel@392:   public class HashSet<T> {
moel@392: 
moel@392:     private readonly Dictionary<T, object> set = new Dictionary<T, object>();
moel@392: 
moel@392:     public bool Add(T value) {
moel@392:       if (set.ContainsKey(value))
moel@392:         return true;
moel@392: 
moel@392:       set.Add(value, null);
moel@392:       return false;
moel@392:     }
moel@392: 
moel@392:     public bool Contains(T value) {
moel@392:       return set.ContainsKey(value);
moel@392:     }
moel@392: 
moel@392:     public void Clear() {
moel@392:       set.Clear();
moel@392:     }
moel@392:   }
moel@392: }