Index was outside the bounds of the array. VB.NET - vb.net

Question

My problem
Index was outside the bounds of the array. when i try to run the code , it generates this error
i have two forms : SIGN IN and SIGN UP , my problem is they don't work together and generates the error attached below
Dim fs As New FileStream("C:\Users\Selmen\Desktop\vb\logs.txt", FileMode.Open, FileAccess.ReadWrite)
Dim sr As New StreamReader(fs)
Dim sw As New StreamWriter(fs)
Dim s As String
Dim t() As String
Dim trouve As Integer = 0
Dim tt() As String
Dim ch As String
ch = TextBox1.Text + "#" + TextBox2.Text + "#" + TextBox3.Text + "#" + TextBox4.Text + "#" + TextBox5.Text
tt = ch.Split("#")
Do While (trouve = 0) And (sr.Peek > -1)
s = sr.ReadLine
t = s.Split("#")
If String.Compare(t(2), tt(2)) = 0 Then
trouve = 1
End If
Loop
If (trouve = 1) Then
MsgBox("user existant")
Else
sw.WriteLine(ch)
Me.Hide()
Form4.Show()
End If
sw.Close()
sr.Close()
fs.Close()
End Sub
If String.Compare(t(2), tt(2)) = 0 Then I get:
IndexOutOfRangeException was unhandled / Index was outside the bounds of the array.

Answer 1

Streams need to be disposed. Instead of using streams you can easily access a text file with the .net File class.
File.ReadAllLines returns an array of lines in the file. We can loop through the lines in a For Each. The lower case c following the "#" tells the compiler that you intend a Char not a String. String.Split expects a Char. Normally, String.Compare is used to order strings in alphabetical order. You just need an =. As soon as we find a match we exit the loop with Exit For.
We don't actually need the array of the text boxes Text property unless there is no match. Putting the elements in braces intializes and fills the array of String.
File.AppendAllLines does what it says. It is expecting an array of strings. As with the text boxes, we put our line to append in braces.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim p = "path to file"
Dim lines = File.ReadAllLines(p)
Dim trouve As Integer
For Each line In lines
Dim thirdField = line.Split("#"c)(2)
If thirdField = TextBox3.Text Then
trouve = 1
Exit For
End If
Next
If trouve = 1 Then
MsgBox("user existant")
Else
Dim tt = {TextBox1.Text, TextBox2.Text, TextBox3.Text, TextBox4.Text, TextBox5.Text}
File.AppendAllLines(p, {String.Join("#", tt)})
Me.Hid3e()
Form4.Show()
End If
End Sub