Operator Overloading in VB.NET

Question

I have a problem with an Generic Class and define the operator overloads associated with it. Question:

How do I set the operator for the following class assuming that the DataType will be any of the numeric types {float,double,Integer,etc.}?

I quite don't understand the concept yet

Public Class Nombre(Of DataType) '' aka Number
    'VALUE
    Private _Value As DataType

    Public Property Value As DataType
        Get
            Return Me._Value
        End Get
        Set(value As DataType)
            Me._Value = value
        End Set
    End Property

    Public Sub New(value As DataType)
        Me._Value = value
    End Sub

    Public Sub Add(x As DataType)
        _Value += x
    End Sub

    Public Sub Subs(x As DataType)
        _Value -= x
    End Sub

    Public Sub Mult(x As DataType)
        _Value = _Value * x
    End Sub

    Public Sub Power(x As DataType)
        _Value = _Value ^ x
    End Sub

    Public Sub inc()
        _Value += 1
    End Sub

    Public Sub dec()
        _Value -= 1
    End Sub

    Public Sub Divide(x As DataType)
        _Value = _Value / x
    End Sub
End Class

score 4 · Accepted Answer · edited May 23 '17 at 12:06

How do I set the operator for the following class assuming that the DataType will be any of the numeric types {float,double,Integer,etc.}?

You can't do that in a type-safe way, since you cannot restrict DataType to classes where +, -, etc. are defined. This is a commonly requested feature which is just not available yet.

You will have to create an IntegerNombre class, a DoubleNombre class, etc. Then you can define operator overloads in the usual way:

Public Shared Operator +(ByVal n1 As IntegerNombre, 
                         ByVal n2 As IntegerNombre) As IntegerNombre
    Return New IntegerNombre(n1._Value + n2._Value)
End Operator

(Of course, you could keep your generic class, turn Option Strict Off and use late binding with Object:

_Value = DirectCast(_Value, Object) + x

...but you really shouldn't.)

Operator Overloading in VB.NET

1 Answers1