Index Val List VB.Net - vb.net

Question

I have a Listbox called ListTxtDrawR4. Every time I select an item, I want to display the value corresponding to the index in a textbox with name TxtNumberListScan.Lines(i). for example, if I select the 5th line in ListTxtDrawR4, I want to display the value of line 5 from TxtNumberListScan in another Textbox. how do I do that?
TxtTop10HighestResult.Text &= Environment.NewLine & TxtNumberListScan.Lines(TxtTop10HighestCount.Lines(0))
TxtTop10HighestResult.Text &= Environment.NewLine & TxtNumberListScan.Lines(TxtTop10HighestCount.Lines(1))
TxtTop10HighestResult.Text &= Environment.NewLine & TxtNumberListScan.Lines(TxtTop10HighestCount.Lines(2))
TxtTop10HighestResult.Text &= Environment.NewLine & TxtNumberListScan.Lines(TxtTop10HighestCount.Lines(3))
TxtTop10HighestResult.Text &= Environment.NewLine & TxtNumberListScan.Lines(TxtTop10HighestCount.Lines(4))
TxtTop10HighestResult.Text &= Environment.NewLine & TxtNumberListScan.Lines(TxtTop10HighestCount.Lines(5))

Answer 1

Names of controls have been changed to protect the innocent. (I watch Dragnet :-)
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'This is just some data to test with
Dim A() As String = {"Mathew", "Mark", "Luke", "John"}
Dim B() As String = {"Peter", "Paul", "James", "Judas"}
ListBox1.Items.AddRange(A)
For Each s In B
TextBox1.Text &= s & Environment.NewLine
Next
TextBox1.Text.TrimEnd() 'Remove final new line
End Sub
Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
Dim index As Integer = ListBox1.SelectedIndex
'Check that the index does not exceed the number of lines.
If index < TextBox1.Lines.Count Then
Dim StringToCopy = TextBox1.Lines(index)
TextBox2.Text &= StringToCopy & Environment.NewLine
End If
End Sub