C# Language Specification - Willy .Net

Chapter 17 Classesthe P property in B hides the P property in A with respect to both reading and writing. Thus, in the statementsB b = new B();b.P = 1; // Error, B.P is read-only((A)b).P = 1; // Ok, reference to A.Pthe assignment to b.P causes a compile-time error to be reported, since the read-only P property in B hides thewrite-only P property in A. Note, however, that a cast can be used to access the hidden P property. end example]Unlike public fields, properties provide a separation between an object’s internal state and its public interface.[Example: Consider the example:class Label{private int x, y;private string caption;public Label(int x, int y, string caption) {this.x = x;this.y = y;this.caption = caption;}public int X {get { return x; }}public int Y {get { return y; }}public Point Location {get { return new Point(x, y); }}public string Caption {get { return caption; }}}Here, the Label class uses two int fields, x and y, to store its location. The location is publicly exposed both asan X and a Y property and as a Location property of type Point. If, in a future version of Label, it becomesmore convenient to store the location as a Point internally, the change can be made without affecting the publicinterface of the class:class Label{private Point location;private string caption;public Label(int x, int y, string caption) {this.location = new Point(x, y);this.caption = caption;}public int X {get { return location.x; }}public int Y {get { return location.y; }}public Point Location {get { return location; }}public string Caption {get { return caption; }}}243