If array is empty error - vb.net

Question

The array is a 9 position array declared as a string, I have 9 text boxes that a user can input data into, each writes to one variable in the array.
I am trying to stop filling the array, and move to print it when the user either fills in all 9 text box's, or stops filling them in when he presses the "write to file" button. From my debugging points, it looks like I get down to the "for" loop, but the program crashes with no errors that I can make heads or tails out of (not syntax or variable)... can anyone see what i'm missing?
Thanks
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim FILE_NAME As String = "C:\Users\foo\test2.txt"
Dim i As Integer
Dim j As Integer
Dim aryText(9) As String
MessageBox.Show(j)
aryText(0) = "[" & TextBox1.Text & "]"
j = 0
MessageBox.Show(j)
If String.IsNullOrWhiteSpace(TextBox2.Text) Then
End
Else
aryText(1) = "*" & TextBox2.Text & "{label: " & "varchar, not null" & "}"
j = j + 1
MessageBox.Show(j)
End If
'If TextBox3.Text IsNot Nothing Then
If String.IsNullOrWhiteSpace(TextBox3.Text) Then
End
Else
aryText(2) = TextBox3.Text & " {label: " & "varchar, null" & "}"
j = j + 1
MessageBox.Show(j)
End If
If String.IsNullOrWhiteSpace(TextBox4.Text) Then
End
Else
aryText(3) = TextBox4.Text & " {label: " & "varchar, not null" & "}"
j = j + 1
MessageBox.Show(j)
End If
If String.IsNullOrWhiteSpace(TextBox5.Text) Then
End
Else
aryText(4) = TextBox5.Text & " {label: " & "varchar, not null" & "}"
j = j + 1
MessageBox.Show(j)
End If
If String.IsNullOrWhiteSpace(TextBox6.Text) Then
End
Else
aryText(5) = TextBox6.Text & " {label: " & "varchar, not null" & "}"
j = j + 1
MessageBox.Show(j)
End If
If String.IsNullOrWhiteSpace(TextBox7.Text) Then
End
Else
aryText(6) = TextBox7.Text & " {label: " & "varchar, not null" & "}"
j = j + 1
MessageBox.Show(j)
End If
If String.IsNullOrWhiteSpace(TextBox8.Text) Then
End
Else
aryText(7) = TextBox8.Text & " {label: " & "varchar, not null" & "}"
j = j + 1
MessageBox.Show(j)
End If
If String.IsNullOrWhiteSpace(TextBox9.Text) Then
End
Else
aryText(8) = TextBox9.Text & " {label: " & "varchar, not null" & "}"
j = j + 1
MessageBox.Show(j)
End If
Dim objWriter As New System.IO.StreamWriter(FILE_NAME, True)
MessageBox.Show(j)
For i = 0 To j
objWriter.WriteLine(aryText(j))
i = i + 1
Next
objWriter.Close()
MessageBox.Show("Text written to file")
End Sub

Answer 1

Please don't debug with MessageBoxes. Visual Studio has a lovely debugger.
VB.net arrays are declared Dim myArray(UpperBound) As String. So with your 9 text boxes you have an upper bound of 8, indexes 0 to 8
You want Exit Sub not End.
A For x = 0 to y...Next works by automatically incrementing x (that is what the Next means, Next x) the default is by one but you can change that by adding a Step. If you attempt to change y you will make a mess. Your For...Next will just write the last value in the array 9 times (aryText(j)) because j doesn't change. Don't increment x in the loop; it increments automatically when Next is called.
No need to mess with i and j; just use a For Each
Using code block for your stream writer ensures all resources are released.
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim FILE_NAME As String = "C:\Users\foo\test2.txt"
Dim aryText(8) As String
Dim msg As String = "Please fill in all the boxes,"
If String.IsNullOrWhiteSpace(TextBox1.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(0) = "[" & TextBox1.Text & "]"
End If
If String.IsNullOrWhiteSpace(TextBox2.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(1) = "*" & TextBox2.Text & "{label: " & "varchar, not null" & "}"
End If
If String.IsNullOrWhiteSpace(TextBox3.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(2) = TextBox3.Text & " {label: " & "varchar, null" & "}"
End If
If String.IsNullOrWhiteSpace(TextBox4.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(3) = TextBox4.Text & " {label: " & "varchar, not null" & "}"
End If
If String.IsNullOrWhiteSpace(TextBox5.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(4) = TextBox5.Text & " {label: " & "varchar, not null" & "}"
End If
If String.IsNullOrWhiteSpace(TextBox6.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(5) = TextBox6.Text & " {label: " & "varchar, not null" & "}"
End If
If String.IsNullOrWhiteSpace(TextBox7.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(6) = TextBox7.Text & " {label: " & "varchar, not null" & "}"
End If
If String.IsNullOrWhiteSpace(TextBox8.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(7) = TextBox8.Text & " {label: " & "varchar, not null" & "}"
End If
If String.IsNullOrWhiteSpace(TextBox9.Text) Then
MessageBox.Show(msg)
Exit Sub
Else
aryText(8) = TextBox9.Text & " {label: " & "varchar, not null" & "}"
End If
Using objWriter As New System.IO.StreamWriter(FILE_NAME, True)
For Each s As String In aryText
objWriter.WriteLine(s)
Next
End Using
MessageBox.Show("Text written to file")
End Sub