A simple wrapper for System.Drawing.Rectangle that allows manipulation of the Top, Right, Bottom and Left properties.

SelectionRectangle.cs

public class SelectionRectangle : IEquatable<SelectionRectangle>
{
    private Rectangle rectangle;

    public int Area
    {
        get { return rectangle.Width * rectangle.Height; }
    }
    public int X
    {
        get { return rectangle.X; }
        set { rectangle.X = value; }
    }
    public int Y
    {
        get { return rectangle.Y; }
        set { rectangle.Y = value; }
    }
    public Point Location
    {
        get { return rectangle.Location; }
        set { rectangle.Location = value; }
    }
    public int Width
    {
        get { return rectangle.Width; }
        set { rectangle.Width = value; }
    }
    public int Height
    {
        get { return rectangle.Height; }
        set { rectangle.Height = value; }
    }
    public int Top
    {
        get { return rectangle.Top; }
        set
        {
            rectangle.Height -= value - rectangle.Y;
            rectangle.Y = value;
        }
    }
    public int Right
    {
        get { return rectangle.Right; }
        set { rectangle.Width = value - rectangle.X; }
    }
    public int Bottom
    {
        get { return rectangle.Bottom; }
        set { rectangle.Height = value - rectangle.Y; }
    }
    public int Left
    {
        get { return rectangle.Left; }
        set
        {
            rectangle.Width -= value - rectangle.X;
            rectangle.X = value;
        }
    }
    public bool IsEmpty
    {
        get { return rectangle.IsEmpty; }
    }

    public SelectionRectangle()
    {
        rectangle = new Rectangle();
    }
    public SelectionRectangle(Point location, Size size)
    {
        rectangle = new Rectangle(location, size);
    }
    public SelectionRectangle(int x, int y, int width, int height)
    {
        rectangle = new Rectangle(x, y, width, height);
    }
    public bool Contains(Point pt)
    {
        return rectangle.Contains(pt);
    }
    public bool Contains(Rectangle rect)
    {
        return rectangle.Contains(rect);
    }
    public bool Contains(int x, int y)
    {
        return rectangle.Contains(x, y);
    }
    public bool Equals(SelectionRectangle other)
    {
        return rectangle.Equals(other.rectangle);
    }
    public void Inflate(Size size)
    {
        rectangle.Inflate(size);
    }
    public void Inflate(int width, int height)
    {
        rectangle.Inflate(width, height);
    }
    public void Intersect(Rectangle rect)
    {
        rectangle.Intersect(rect);
    }
    public bool IntersectsWith(Rectangle rect)
    {
        return rectangle.IntersectsWith(rect);
    }
    public void Offset(Point pos)
    {
        rectangle.Offset(pos);
    }
    public void Offset(int x, int y)
    {
        rectangle.Offset(x, y);
    }
}