Here's a custom predicate wrapper class I got from visual basic forums. I'll be converting
and posting the C# equivalent for this.
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21 | Public Delegate Function PredicateWrapperDelegate(Of T, A) _
(ByVal item As T, ByVal argument As A) As Boolean
Public Class PredicateWrapper(Of T, A)
Private _argument As A
Private _wrapperDelegate As PredicateWrapperDelegate(Of T, A)
Public Sub New(ByVal argument As A, _
ByVal wrapperDelegate As PredicateWrapperDelegate(Of T, A))
_argument = argument
_wrapperDelegate = wrapperDelegate
End Sub
Private Function InnerPredicate(ByVal item As T) As Boolean
Return _wrapperDelegate(item, _argument)
End Function
Public Shared Widening Operator CType( _
ByVal wrapper As PredicateWrapper(Of T, A)) _
As Predicate(Of T)
Return New Predicate(Of T)(AddressOf wrapper.InnerPredicate)
End Operator
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4 | Public Shared Function FindIndexTrackNumber(ByVal SysTrack As SystemTrack, ByVal searchArg As Integer) As Boolean
'Searches for the SystemTrack with TrackNumber searchArg
Return SysTrack.ID.Equals(searchArg)
End Function
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14 | Dim SearchNumber As Integer = 456
Dim Index As Integer
Dim SystemTracks As New List(Of SystemTrack)
SystemTracks.Add(New SystemTrack With {.ID = 111, .Title = "Help Me", .Author = "Greg Phil"})
SystemTracks.Add(New SystemTrack With {.ID = 222, .Title = "Help Me1", .Author = "James Nelson"})
SystemTracks.Add(New SystemTrack With {.ID = 456, .Title = "Help Me2", .Author = "Tom Enigma"})
SystemTracks.Add(New SystemTrack With {.ID = 12, .Title = "Help Me3", .Author = "Lord Brown"})
Index = SystemTracks.FindIndex(New PredicateWrapper(Of SystemTrack, Integer)(SearchNumber, AddressOf SystemTrack.FindIndexTrackNumber))
If Index <> -1 Then
Console.WriteLine("Sytem Track has been found at: " & Index)
Else
Console.WriteLine("System Track not found! ")
End If
Console.ReadLine()
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:)
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