Please help!

radioactiveman

Does anyone know in VB, can you override a method "on the fly" like you can in java?

Like in java, you can do:

MyClass blah = new MyClass() {

Protected void methodToOverRide() {
// actually do something different in here to what is actually in the method in MyClass
}

};

Where MyClass is a class you have already, but you're creating a new instance of it on the fly and overriding one of its methods that you need to change.

How the fup do you do this in vb ?

Thanks!

NeverSayDie

I don't know much about Java, but I gather that's an anonymous class system of some sort that it supports, AFAIK .NET (I'm assuming you mean VB.NET) doesn't support anonymous classes like that. There may be some arcane way of achieving that using the System.Reflection namespace, but I wouldn't care to speculate
There is a system for "extension methods" in C# (VB too I assume), but you can only use that to stick stuff on to existing classes, not override things. Another point to note is that if you do subclass the existing version, unlike (AFAIK) Java, methods aren't virtual by default in .NET.

Edit; I gather those kind of anonymous classes are usually used for event handling behaviours in Java - if you want to deal with that kind of thing in .NET, "delegates" would be the mechanism to use, Google will turn up lots on that.

Evil Phil

Would Lambda Expressions be of any use?

radioactiveman

Hi thanks for the suggestions, in the end I just coded it as an inner class. Probably just as good because even if I did figure out a way to do this there's no guarantee another person will be able to read it easily
NeverSayDie: it's a thing you can do in java to define an anonymous class on the fly. It's very handy but it's definitely a specific java trick, it would be different in other languages...

Reku

radioactiveman wrote: »

Does anyone know in VB, can you override a method "on the fly" like you can in java?

Like in java, you can do:

MyClass blah = new MyClass() {

Protected void methodToOverRide() {
// actually do something different in here to what is actually in the method in MyClass
}

};

Where MyClass is a class you have already, but you're creating a new instance of it on the fly and overriding one of its methods that you need to change.

How the fup do you do this in vb ?

Thanks!

What you're describing there is not overriding. To override a method you need to create an alternative version of the method in a subclass of the class with the original method in it.
e.g.

Class blah extends MyClass
{

Protected void methodToOverRide()
{
// actually do something different in here to what is actually in the
method in MyClass
}
}

With what you've given above in order to call the method in MyClass you need to call blah.methodToOverRide(); from the class, which to the system is completely different to just methodToOverRide();

The following page seems to show how to do the same in visual basic:
http://www.startvbdotnet.com/oop/class.aspx

Altered to match your example I think that would be (I don't know visual basic:( hopefully someone who does can fix any errors)

Dim blah As New MyClass()
'creating a object blah for MyClass class

Sub methodToOverRide()
'actually do something different in here to what is actually in the method in
'MyClass
End Sub