Load textfile containing names to a textbox - vb.net

Question

I am attempting to load a text file that contains a list of names into a text box using a button on the form. Also, I would like to display the following name after the button is pressed. I have been trying to successfully implement this code for several days however, my program loads all names at once. Would anyone be able to provide advice about loading text files?
Below is a copy of my code:
firstName.Multiline = True 'Variable contains first name.
lastName.Multiline = True 'Variable contains last name.
Dim fullName = "" 'Variable containing full name found in text file
Dim lines = IO.File.ReadAllLines("input.txt") 'loading input file located in Debug folder.
For Each i As String In lines
Dim fullNames = lines.Where(Function(line) line.Contains(" "))
If fullNames.Any() Then
Dim fullNamesSplit = fullNames.Select(Function(line) line.Split(" "c))
Dim firstNames = fullNamesSplit.Select(Function(line) line(0))
Dim lastNames = fullNamesSplit.Select(Function(line) line(1))
firstName.Lines = firstNames.ToArray()
lastName.Lines = lastNames.ToArray()
fullName = String.Join(Environment.NewLine, fullNames)
Else
firstName.Text = ""
lastName.Text = ""
End If
displayInfo.Items.Add(fullName)
Next

Answer 1

There's no loop. Load the names into an array, initialise an index variable to 0 and load the name at that index. Each time you click the Button, increment the index and load the name at that index. Once you reach the end, you can either wrap to the beginning or tell the user there are no more names. If you don't want to wrap then an even better option would be to load the names into a queue and then just dequeue on each click.

Answer 2

I have been able to display the names in order however I did not use a looping structure. However, the names are output multiple times in the text box after the button is clicked.
Dim i As Integer = 0
Private Sub NextAvName_Click(sender As Object, e As EventArgs) Handles nextAvName.Click
firstName.Multiline = True 'Variable contains first name.
lastName.Multiline = True 'Variable contains last name.
Dim fullName = "" 'Variable containing full name found in text file
Dim lines = IO.File.ReadAllLines("input.txt") 'loading input file located in Debug folder.
lines = lines.ToArray
Dim element As String
element = lines(i)
Dim fullNames = element.Where(Function(line) element.Contains(" "))
If fullNames.Any() Then
Dim fullNamesSplit = fullNames.Select(Function(line) element.Split(" "c))
Dim firstNames = fullNamesSplit.Select(Function(line) line(0))
Dim lastNames = fullNamesSplit.Select(Function(line) line(1))
firstName.Lines = firstNames.ToArray()
lastName.Lines = lastNames.ToArray()
fullName = String.Join(Environment.NewLine, fullNames)
Else
firstName.Text = ""
lastName.Text = ""
End If
displayInfo.Items.Add(fullName)
i = i + 1