LINQ Query Null Error - vb.net

Question

I have am making an email contact search, where I am supposed to open a text file using the OpenFileDialog, and then split it to an array and search using LINQ. I have the openFileDialog working, but when I run my LINQ query, I get the object reference not set to an instance of an object error. Option Infer is on, and as far as I can tell this is set up exactly like some of the examples in my textbook. Can anyone point me in the right direction??? (textFile is defined as a class variable above the first button code: "Dim textFile(2) As String".
Code:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles BtnOpen.Click
OpenFileDialog1.ShowDialog()
textFile(2) = OpenFileDialog1.FileName
lstOutput.DataSource = IO.File.ReadAllLines(textFile(2))
lstOutput.SelectedItem = Nothing
End Sub
Private Sub btnNameSearch_Click(sender As Object, e As EventArgs) Handles btnNameSearch.Click
Dim queryName = From line In textFile
Let data = line.Split(","c)
Let firstName = data(0)
Let lastName = data(1)
Let email = data(2)
Where firstName = txtName.Text
Select firstName, lastName, email
lstName.DataSource = queryName.ToList
End Sub
Edit: Code breaks on line 21 "Let data=line.Split(","c)

Answer 1

You're using the filename as the string that LINQ is querying against. You need to use the file contents itself.
Change your code to something like this:
Private lines() As String
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles BtnOpen.Click
If OpenFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
textFile(2) = OpenFileDialog1.FileName
lines = IO.File.ReadAllLines(textFile(2))
lstOutput.DataSource = lines
lstOutput.SelectedItem = Nothing
End If
End Sub
Private Sub btnNameSearch_Click(sender As Object, e As EventArgs) Handles btnNameSearch.Click
Dim queryName = From line In lines
Let data = line.Split(","c)
Let firstName = data(0)
Let lastName = data(1)
Let email = data(2)
Where firstName = txtName.Text
Select firstName, lastName, email
lstName.DataSource = queryName.ToList
End Sub