vb.net fix issue with dup remover

hello,
I am having a little issue this dup remover source I have..

For example:
> ids_database.txt has lines by lines like this

65098908|name1|last1
98046545|name2|last2
65098998|name3|last3
25989808|name4|last4

>new_ids.txt has lines by line like this

65098908|this_is|a_dup_id
98046584|name5|last5
65068945|name6|last6
32106890|name7|last7

when you run you should see this 3 lines in printed to "ids_to_fix.txt"

98046584|name5|last5
65068945|name6|last6
32106890|name7|last7

thats' because those 3 ids before the "|" pipe are not in the database.
everything after the pipe is ignored, this is just for checking IDs against from ids_database..if not found then create a text file..

its not happening whats going on ?

Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.IO

Module dupRemover
    Sub Main()
        Console.WriteLine("{0}: Start", DateTime.Now)

        Dim data As New HashSet(Of String)()

        Try
            ' read your main IDs
            Using reader As New StreamReader("ids_database.txt")
                While reader.Peek() > 0
                    data.Add(reader.ReadLine().Trim())
                End While
            End Using

            Dim ids_to_fix As New List(Of String)()

            'read new IDs and if they are not in data - add them
            Using reader As New StreamReader("new_ids.txt")
                Dim tempArr As New List(Of String)
                tempArr.AddRange(String.Join(",", data.ToArray()).ToLower.Split("|".ToCharArray(), StringSplitOptions.RemoveEmptyEntries))
                While reader.Peek() > -1
                    Dim sLine As String = reader.ReadLine().Trim()
                    Dim firstPart As String = sLine.Split(",")(0)
                    If Not tempArr.Contains(firstPart.ToLower) Then
                        data.Add(sLine)
                        ids_to_fix.Add(sLine)
                    End If
                End While
            End Using

            ' Write new IDs back to ids_to_fix
            Using writer As New StreamWriter("ids_to_fix.txt")
                For Each sLine As String In ids_to_fix
                    writer.WriteLine(sLine)
                Next
            End Using

            ' Eventually, write everything back to database
            Using writer As New StreamWriter("ids_database.txt")
                For Each sLine As String In data
                    writer.WriteLine(sLine)
                Next
            End Using
        Catch ex As Exception
            Console.WriteLine("An error occurred - {0}", ex.Message)
        End Try

        Console.WriteLine("{0}: End", DateTime.Now)
        Console.ReadLine() 'pause
    End Sub
End Module

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