So I know I can't actually access methods and attributes of a subclass from it's parent. But I have a program which stores Vehicles in an array (NOT arraylist - its homework). The Vehicles then initialize into either Airplane, Boat, or a Car object derived from the Vehicle class. These subclasses have attributes which are unique, and I'm wondering as to how I could go about accessing these?
Here's some (simplified) relevant code:
Vehicle[] vehicles = new Vehicle[20];
vehicles[0] = new Airplane();
// Setting an attribute of the superclass
vehicles[0].Make = "Boeing";
// Set an attribute from the Airplane class
vehicles[0].Engine = "Jet"; //(obviously this doesn't work)
How could I go about working around this? I've researched for a couple hours but I'm stumped by this one problem.
Thanks :)
You can access a reference through the type of its declaration. Because you declare the array to be of Vehicle, you cannot directly access subclass members.
To do so, initialize the object separately from the collection that contains it:
var jet = new Airplane();
jet.Make = "Boeing";
jet.Engine = "Jet";
vehicles[0] = jet;
Alternatively, use an object initializer:
vehicles[0] = new Airplane
{
Make = "Boeing",
Engine = "Jet"
};
It would be quite nonsensical to cast it back just after instantiating it, but you could do that as well:
vehicles[0] = new Airplane();
((Airplane)vehicles[0]).Make = "Boeing";
((Airplane)vehicles[0]).Engine = "Jet";
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