How do I fix a Null reference exception in Visual basic?

Asked Jul 17 '16 at 23:30

Active Jul 17 '16 at 23:30

Viewed 22 times

I don't know why this keeps happening but when ever I try to imput changes to the file nothing will happen. I added an exception to see if it doesn't happen but it keeps happening. Please help q.q

Private Sub subBut_Click(sender As Object, e As EventArgs) Handles         subBut.Click
    If gradeBox.Text <> String.Empty Then
        Dim grade As String = Convert.ToInt32(gradeBox.Text)
            If grade > 0 Then
             ' imputs grade to file
            writer.WriteLine(grade) ' error 
            Else
            Application.Exit()
            End If
    End If
End Sub

asked Jul 17 '16 at 23:30

Carl Zahner

3

Turn on `Option Strict` - this makes no sense at all: `Dim grade As String = Convert.ToInt32(gradeBox.Text)`.. What is `writer` and where did it come from? – Ňɏssa Pøngjǣrdenlarp Jul 17 '16 at 23:33
You probably forgot the `New` keyword when creating your `writer` variable. – Visual Vincent Jul 18 '16 at 09:57

How do I fix a Null reference exception in Visual basic?

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