Mega Code Archive
A base class reference can refer to a derived class object
<![CDATA[
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// A base class reference can refer to a derived class object.
using System;
class X {
public int a;
public X(int i) {
a = i;
}
}
class Y : X {
public int b;
public Y(int i, int j) : base(j) {
b = i;
}
}
public class BaseRef {
public static void Main() {
X x = new X(10);
X x2;
Y y = new Y(5, 6);
x2 = x; // OK, both of same type
Console.WriteLine("x2.a: " + x2.a);
x2 = y; // still Ok because Y is derived from X
Console.WriteLine("x2.a: " + x2.a);
// X references know only about X members
x2.a = 19; // OK
// x2.b = 27; // Error, X doesn't have a b member
}
}
]]>