Scott,
To expand on Ken's comments.
VB.NET allows you to overload methods (Subs, Functions & Properties).
Overloading means creating the same method (same name) with a different
parameter list. When overloading only the types of the parameters are
considered the return type of a Function or Property is not.
For example if I was creating a class where a method sometimes expects a
String & sometimes expects an Integer I would overload the method.
Public Class Widget
Public Sub DoSomething(ByVal value As String)
End Sub
Public Sub DoSomething(ByVal value As Integer)
End Sub
End Class
Then when using the Widget class
Dim theWidget As New Widget
' this will call the string version of DoSomething
theWidget.DoSomething("Hello World")
' this will call the integer version of DoSomething
theWidget.DoSomething(100)
One advantage of doing this is that you can encapsulate the call to
Integer.ToString in DoSomething(Integer) rather then converting the Integer
& call DoSomething(String) in a 20+ places. For one or two I'm not sure I
would overload DoSomething. Which is why Console.Write has overloads for all
of the "primitive" types (String, Byte, Char, Integer, Short, Long, Single,
Double, ...)
Other classes may overload DoSomething as what happens when an Integer is
passed is different then when a String is passed, especially when the
Integer is the position in a collection, while String is the name of the
item in a collection.
For details see:
http://msdn.microsoft.com/library/d...ry/en-us/dndotnet/html/overloadingmethods.asp
As odd as it may sound Overloading is Overloading Polymorphism. As there are
4 kinds of polymorphism.
1: Coercion - a single abstraction serves several types through conversion
2: Overloading - a single identifier denotes several abstractions
3: Parametric - an abstraction operates uniformly across different types
4: Inclusion - an abstraction operates through an inclusion relation
Within VB.NET the math operators are examples of coercion polymorphism. You
can use the + operator on two integers to add them, you can also use the +
operator on singles & doubles which also adds them. In other words the +
operator is 'overloaded' for different built-in types. While C# allows
developers to define overload operators. VB.NET needs to wait for VS.NET
2005 (Whidbey, due out later in 2005) for operator overloading.
Within VB.NET we are allowed to overload members (overloading polymorphism)
within a single type as long as the parameter signatures are unique. Across
types we are free to overload members irregardless of signatures. Of course
VB.NET does define certain rules for overloading such as you cannot have a
function & a field with exactly the same name. ;-)
We will need to wait for VS.NET 2005 (Whidbey, due out later in 2005) to
gain Parametric Polymorphism (a.k.a Generics).
Within VB.NET Inclusion polymorphism is subtype polymorphism. Using Inherits
or Implements to define a type that is also another type (where type is a
Class, Structure, or Interface). Normally when developers are talking
Polymorphism they are referring to this type of Polymorphism.
Polymorphism definitions taken from:
http://www.javaworld.com/javaworld/jw-04-2001/jw-0413-polymorph.html
Hope this helps
Jay
