c# - Overriding property setter -

i'm making program there balls bouncing around, want inherit class , make new 1 impossible set it's velocity

i've tried doesn't anyting

public class ball {     public ball(double posx, double posy, double rad, vector vel) {         pos = new point(posx, posy);         rad = rad;         vel = vel;     }     public double rad { get; set; }      public point pos { get; set; }     public vector vel { get; set; } }  public class staticball : ball {     public staticball(double posx, double posy, double rad)          : base(posx, posy, rad, new vector(0, 0)) {      }     public vector vel {         { return vel; }         set { vel = vel; }     } } 

how should this?

i'm making program there balls bouncing around, want inherit class , make new 1 impossible set it's velocity

your requirement violates substitution principle. if velocity of ball can changed, velocity of class inheriting ball must changeable.

solution: instead of inheriting constantspeedball ball, create new base class ballbase , inherit both constantspeedball , changingvelocityball it.