Uses delegates to sort random numbers (ascending or descending) : Delegate « Class Module « VB.Net Tutorial

1. VB.Net Tutorial
2. Class Module
3. Delegate

Public Class Tester


   Private Shared Function SortAscending(ByVal element1 As Integer, _
      ByVal element2 As Integer) As Boolean

      Return element1 > element2
   End Function ' SortAscending

   Private Shared Function SortDescending(ByVal element1 As Integer, _
      ByVal element2 As Integer) As Boolean

      Return element1 < element2
   End Function ' SortDescending

   Public Shared Sub Main
      Dim mBubbleSort As New BubbleSort()

      Dim mElementArray As Integer() = New Integer(9) {}

      Dim randomNumber As Random = New Random()
      Dim i As Integer

      ' create String with 10 random numbers
      For i = 0 To mElementArray.GetUpperBound(0)
         mElementArray(i) = randomNumber.Next(100)
         Console.WriteLine(mElementArray(i))
      Next
    
      mBubbleSort.SortArray(mElementArray, AddressOf SortAscending)

      For i = 0 To mElementArray.GetUpperBound(0)
         Console.Write(mElementArray(i) & " " )
      Next
      Console.WriteLine()
      mBubbleSort.SortArray(mElementArray, AddressOf SortDescending)

      For i = 0 To mElementArray.GetUpperBound(0)
         Console.Write(mElementArray(i) & " " )
      Next

   End Sub

End Class

Public Class BubbleSort
   Public Delegate Function Comparator( _
      ByVal element1 As Integer, _
      ByVal element2 As Integer) As Boolean

   Public Sub SortArray(ByVal array As Integer(), _
      ByVal Compare As Comparator)

      Dim i, pass As Integer

      For pass = 0 To array.GetUpperBound(0)

         For i = 0 To array.GetUpperBound(0) - 1
            If Compare(array(i), array(i + 1)) Then
               Swap(array(i), array(i + 1))
            End If
         Next ' inner loop
      Next ' outer loop
   End Sub ' SortArray

   Private Sub Swap(ByRef firstElement As Integer, _
      ByRef secondElement As Integer)

      Dim hold As Integer

      hold = firstElement
      firstElement = secondElement
      secondElement = hold
   End Sub ' Swap
End Class

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