Custom Predicate

Public Class CustomPredicate
    Public Enum searches As Integer
        Contains = 1
        IsEqualTo = 2
        DoesntContain = 3
    End Enum
    Public FilterKey As String
    Public Pred As Predicate(Of String)
    Public Sub New(ByVal type As searches,Optional ByVal Key as String = Nothing)
      If Not(Key Is Nothing)  Then
         FilterKey = Key
      End If
        Select Case type
            Case searches.Contains
                Pred = AddressOf Contains
            Case searches.DoesntContain
                Pred = AddressOf DoesntContain
            Case searches.IsEqualTo
                Pred = AddressOf IsEqualTo
        End Select
    End Sub
    Public Function Contains(ByVal s As String) As Boolean
        Return InStr(s.ToLower, FilterKey.ToLower, CompareMethod.Binary) > 0
    End Function
    Public Function DoesntContain(ByVal s As String) As Boolean
        Return Not (InStr(s.ToLower, FilterKey.ToLower, CompareMethod.Binary) > 0)
    End Function
    Public Function IsEqualTo(ByVal s As String) As Boolean
        If s.ToLower = FilterKey.ToLower Then
            Return True
        Else
            Return False
        End If
    End Function
End Class

Dim l as New List(Of String)
        l.Add("1")
        l.Add("2")
        l.Add("3")
        l.Add("deez")
        l.Add("doze")
Dim myPredicate As New CustomPredicate(CustomPredicate.searches.Contains)  

        myPredicate.FilterKey = "e"

Dim str() as String = l.FindAll(myPredicate.Pred)

'str(0) = "deez"    str(1) = "doze"


'another example

Dim str2() as String = l.FindAll(New CustomPredicate(CustomPredicate.searches.DoesntCon  tain, "e").Pred)

'str(0) = "1"   str(1) = "2"   str(2) = "3"