Stuck on my Login Panel - vb.net

Question

It keeps returning null and I was hoping someone could clean it up for me and see if there is a simpler way to do this. I'm really wanting to start making my game.
Public Class frmLogin
Private Sub mnuExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuExit.Click
Application.Exit()
End Sub
Private Sub btnCreate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCreate.Click
Dim FILE_NAME As String = "C:\Users\Nick\documents\visual studio 2010\Projects\LoginFixed\Accounts\" + Me.txtCUser.Text
If File.Exists(FILE_NAME) Then
Me.lblExists.Text = "Username has already been created!"
Return
End If
If txtCUser.Text.Length < 3 Then
Me.lblExists.Text = "Must have atleast 3 characters."
Return
End If
Dim writeFile As StreamWriter = File.CreateText("C:\Users\Nick\documents\visual studio 2010\Projects\LoginFixed\Accounts\" + Me.txtCUser.Text)
writeFile.WriteLine("User: " + Me.txtCUser.Text) ' user
writeFile.WriteLine("Pass: " + Me.txtCPass.Text) ' pass
writeFile.WriteLine("-------------------")
writeFile.Close()
End Sub
Private Function GetLine(ByVal fileName As String, ByVal line As Integer) As String
Try
If File.Exists(fileName) = False Then
Using sr As New StreamReader("C:\Users\Nick\documents\visual studio 2010\Projects\LoginFixed\Accounts\" + Me.txtUser.Text)
For i As Integer = 1 To line - 1
sr.ReadLine()
Next
Return (sr.ReadLine())
sr.Close()
End Using
End If
Catch ex As Exception
Return ex.Message
End Try
End Function
Private Sub btnLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogin.Click
Dim FILE_NAME As String = "C:\Users\Nick\documents\visual studio 2010\Projects\LoginFixed\Accounts\" + Me.txtUser.Text
If File.Exists(FILE_NAME) And Me.txtPassword.Text = (GetLine(FILE_NAME, 2).Substring(6)) Then
Me.lblLoggedIn.Text = "Logged"
ElseIf File.Exists(FILE_NAME) = False Then
Me.lblLoggedIn.Text = "You must create an account! Navigate to TabPage2."
End If
End Sub
End Class
It would really help a lot. I just started vb not to long ago maybe about a week or two.

Answer 1

Three things. First, in GetLine() you're attempting to open the file if it does NOT exist; change from False to True. Second, you should open the file name that was passed in, not a hard-coded one that uses the value from a TextBox. Lastly, to get rid of the warning, you need to return something if the file does not exist:
Change GetLine() to:
Private Function GetLine(ByVal fileName As String, ByVal line As Integer) As String
Try
If File.Exists(fileName) Then
Using sr As New StreamReader(fileName)
For i As Integer = 1 To line - 1
sr.ReadLine()
Next
Return sr.ReadLine()
End Using
Else
Return "{File Not Found: " & fileName & "}"
End If
Catch ex As Exception
Return ex.Message
End Try
End Function
*You were returning the exception as a string, so I followed that model with the file not found error. How will you know, though, if you have an actual error, or if the line in the file was exactly like the "error" being returned?