C#

public class ReverseTrackBar : TrackBar
{
  private new int Value
  {
    get { return (((TrackBar)base).Maximum - (((TrackBar)base).Value - this.Minimum)); }
    set { ((TrackBar)base).Value = (((TrackBar)base).Maximum - ((int)value - this.Minimum)); }
  }
  private new int Maximum
  {
    get { return ((TrackBar)base).Maximum; }
    set
    {
      int val = this.Value;
      ((TrackBar)base).Maximum = (int)value;
      this.Value = val;
    }
  }
  public ReverseTrackBar()
  {
    this.Value = 0;
  }
}

Heritos Gger wrote:

However, the compiler says "Use of keyword 'base' is not valid in this context".

public new int Value<br />
{<br />
   get { return (base.Maximum - (base.Value - this.Minimum)); }<br />
   protected set { base.Value = base.Maximum - (value - this.Minimum); }<br />
}