Public Class Form1


     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim a() As String = {"4", "5", "10", "12", "14", "15", "7", "8", "9", "3", "18", "16", "15", "100", "13", "55"}
        Dim sc As New NumericComparer(True)
        Array.Sort(a, sc)
        ListView1.Items.Clear()
        For i As Integer = 0 To a.Length - 1
            ListBox1.Items.Add(a(i))
        Next
    End Sub
End Class

Public Class NumericComparer
    Implements IComparer
    Dim mText As Boolean = False
    Public Sub New(ByRef sorttype As NumericSort)
        mText = sorttype
    End Sub

    Public Enum NumericSort
        Textual = True
        Numerical = False
    End Enum

    ' Compare the two employees.
    Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer _
    Implements System.Collections.IComparer.Compare
        If mText = False Then
            Dim txtx As Double = CDbl(x)
            Dim txty As Double = CDbl(y)
            Select Case True
                Case txtx < txty : Return -1
                Case txtx = txty : Return 0
                Case txtx > txty : Return 1
            End Select
        Else
            Dim txtx As String = CStr(x)
            Dim txty As String = CStr(y)
            Return String.Compare(txtx, txty)
        End If

    End Function
End Class