class A
{
public virtual int one()
{
return 100;
}
public virtual int two()
{
return 200;
}
public virtual int three()
{
return this.one();
}
}
class B : A
{
public override int one()
{
return 300;
}
public override int two()
{
return this.one();
}
public override int three()
{
return开发者_开发问答 base.three();
}
}
class Program
{
static void Main(string[] args)
{
A b = new B();
Console.WriteLine(b.three());
}
}
Why does this code return "300"?
Because it's virtual
.
The whole point of virtual
methods is that you always call the overridden version.
That is the definition of an override
.
The virtual
keyword basically means, "Subclasses can override this method".
The override
keyword basically means, "My base class has a virtual method that I am redefining"
I think your confusion is because the this.one()
is called from the class A
. But, the this
still refers to an instance of the class B
, which is why the method on B
is called.
What @SLaks said.
But specifically, b.three()
invokes B.three
, which invokes A.three
, which invokes B.one
.
I think when you say return base.three(); in the overridden method you should acutaly be calling return this.three(); other wise you'll be accessing the base class which is A.
精彩评论