Private Sub CheckRequiredFields(sender As Object, e As EventArgs) Handles txtQuestion.TextChanged, radMultipleChoice.Click, radTrueFalse.Click, radChoiceA.Click,
        radChoiceB.Click, radChoiceC.Click, txtChoiceA.TextChanged, txtChoiceB.TextChanged, txtChoiceC.TextChanged, radTrue.Click, radFalse.Click,
        radResponse.Click, txtMarks.TextChanged
        If Me.txtQuestion.Text IsNot Nothing Then
            Select Case type
                Case "Multiple Choice"
                    'At least one radio button must be checked and all textboxes must be filled
                    If (Me.radChoiceA.Checked Or Me.radChoiceB.Checked Or Me.radChoiceC.Checked) _
                        And Not Me.txtChoiceA.Text = Nothing And Not Me.txtChoiceB.Text = Nothing And Not Me.txtChoiceC.Text = Nothing Then
                        Me.btnAdd.Enabled = True
                    Else
                        Me.btnAdd.Enabled = False
                    End If
                Case "True/False"
                    'Either one of the radio buttons need to be selected
                    If Me.radTrue.Checked Or Me.radFalse.Checked Then
                        Me.btnAdd.Enabled = True
                    Else
                        Me.btnAdd.Enabled = False
                    End If
                Case "Written Response"
                    'Written Response
                    If Me.radResponse.Checked Then
                        'A mark needs to be entered
                        If IsNumeric(Me.txtMarks.Text) Then
                            Me.btnAdd.Enabled = True
                        Else
                            Me.btnAdd.Enabled = False
                        End If
                    End If
            End Select
        Else
            Me.btnAdd.Enabled = False
        End If