Only add String as new Item to Listview if New

[condonethis]

Using the following code to add results from sql to a listview. Is there anyway that I can make a comparison from the reader against all currently existing item strings? Thanks in advance.

LstResults.Items.Clear()
        If con.State <> ConnectionState.Open Then
            Try
                con.Close()
            Catch ex As Exception
 
            End Try
            con.Open()
        End If
        Dim comm As New SqlCommand("select * from maxcom WHERE LastName like '%" & TxtLastName.Text & "%' OR FirstName like '%" & TxtLastName.Text & "%'", con)
        ' OR Position like '%" & TxtLastName.Text & "%'"
        ' OR FirstName like '%" & TxtLastName.Text & "%' OR Position like '%" & TxtLastName.Text & "%' OR "
        Try
            Dim reader As SqlDataReader = comm.ExecuteReader()
            While reader.Read()
                LstResults.Items.Add(reader("FirstName").ToString() & " " & reader("LastName").ToString() & "  " & reader("Extension").ToString() & "  " & reader("DIDNumber").ToString())
                LstResults.Items.Add("-----------------------------------------------------------------------------------------------------------------------------------------------------------------")
            End While
            reader.Close()
        Catch ex As Exception
 
        End Try
        If TxtLastName.Text.ToString.Contains(Chr(32)) Then
            Dim line As String = TxtLastName.Text.ToString
            Dim i As Integer
            Dim aryTextFile() As String
 
            aryTextFile = line.Split(Chr(32))
 
            For i = 0 To UBound(aryTextFile)
                Dim comm2 As New SqlCommand("select * from maxcom WHERE LastName like '%" & aryTextFile(i).ToString & "%' OR FirstName like '%" & aryTextFile(i).ToString & "%'", con)
                Dim reader As SqlDataReader = comm2.ExecuteReader()
                While reader.Read()
                    LstResults.Items.Add(reader("FirstName").ToString() & " " & reader("LastName").ToString() & "  " & reader("Extension").ToString() & "  " & reader("DIDNumber").ToString())
                    LstResults.Items.Add("-----------------------------------------------------------------------------------------------------------------------------------------------------------------")
                End While
                reader.Close()
 
            Next i
        End If
        con.Close()
        TxtLastName.Text = ""
        TxtLastName.Focus()