Delete duplicates from list - vb.net

Question

I have the following class :
Public Class titlesclass
Public Property Link As String
Public Property Title As String
Public Function Clear()
Link.Distinct().ToArray()
Title.Distinct().ToArray()
End Function
End Class
And the following code :
For Each title As Match In (New Regex(pattern).Matches(content)) 'Since you are only pulling a few strings, I thought a regex would be better.
Dim letitre As New titlesclass
letitre.Link = title.Groups("Data").Value
letitre.Title = title.Groups("Dataa").Value
lestitres.Add(letitre)
'tempTitles2.Add(title.Groups("Dataa").Value)
Next
I tried to delete the duplicated strings using the simple way
Dim titles2 = lestitres.Distinct().ToArray()
And calling the class function :
lestitres.Clear()
But the both propositions didn't work , i know that i'm missing something very simple but still can't find what it is

Answer 1

Easier to use a class that already implements IComparable:
Dim query = From title In Regex.Matches(content, pattern).Cast(Of Match)
Select Tuple.Create(title.Groups("Data").Value, title.Groups("Dataa").Value)
For Each letitre In query.Distinct
Debug.Print(letitre.Item1 & ", " & letitre.Item2)
Next
or Anonymous Types:
Dim query = From title In Regex.Matches(content, pattern).Cast(Of Match)
Select New With {Key .Link = title.Groups("Data").Value,
Key .Title = title.Groups("Dataa").Value}
For Each letitre In query.Distinct
Debug.Print(letitre.Link & ", " & letitre.Title)
Next

Answer 2

Ok, Since I notice you are using a ClassHere is one option you can do in order to not add duplicate items to your List within a class.I'm using a console Application to write this example, it shouldn't be too hard to understand and convert to a Windows Form Application if need be.
Module Module1
Sub Main()
Dim titlesClass = New Titles_Class()
titlesClass.addNewTitle("myTitle") ''adds successfully
titlesClass.addNewTitle("myTitle") '' doesn't add
End Sub
Public Class Titles_Class
Private Property Title() As String
Private Property TitleArray() As List(Of String)
Public Sub New()
TitleArray = New List(Of String)()
End Sub
Public Sub addNewTitle(title As String)
Dim added = False
If Not taken(title) Then
Me.TitleArray.Add(title)
added = True
End If
Console.WriteLine(String.Format("{0}", If(added, $"{title} has been added", $"{title} already exists")))
End Sub
Private Function taken(item As String) As Boolean
Dim foundItem As Boolean = False
If Not String.IsNullOrEmpty(item) Then
foundItem = Me.TitleArray.Any(Function(c) -1 < c.IndexOf(item))
End If
Return foundItem
End Function
End Class
End Module
Another option would be to use a HashSet, It will never add a duplicate item, so even if you add an item with the same value, it wont add it and wont throw an error
Sub Main()
Dim titlesClass = New HashSet(Of String)
titlesClass.Add("myTitle") ''adds successfully
titlesClass.Add("myTitle") '' doesn't add
For Each title As String In titlesClass
Console.WriteLine(title)
Next
End Sub
With all of that aside, have you thought about using a Dictionary so that you could have the title as the key and the link as the value, that would be another way you could not have a list (dictionary) contain duplicate items