Mega Code Archive
A base class reference can refer to a derived class object
<![CDATA[
using System;
class BaseClass {
public int a;
public BaseClass(int i) {
a = i;
}
}
class DerivedClass : BaseClass {
public int b;
public DerivedClass(int i, int j) : base(j) {
b = i;
}
}
class MainClass {
public static void Main() {
BaseClass x = new BaseClass(10);
BaseClass x2;
DerivedClass y = new DerivedClass(5, 6);
x2 = x; // OK, both of same type
Console.WriteLine("x2.a: " + x2.a);
x2 = y; // Ok because DerivedClass is derived from BaseClass
Console.WriteLine("x2.a: " + x2.a);
// BaseClass references know only about BaseClass members
x2.a = 19; // OK
// x2.b = 27; // Error, BaseClass doesn't have a b member
}
}
x2.a: 10
x2.a: 6
]]>