[VB.NET] Programa CAPTCHA Doğrulaması Ekleme

Private Cevap As String = Nothing
Private Function KodOlustur() As String
Dim Operatorler As String() = {"+", "-"}
Baslangic:
Dim Sayi1 As Integer = New Random().Next(1, 9)
Dim Sayi2 As Integer = New Random().Next(1, 9)
If Sayi1 = Sayi2 Then GoTo Baslangic
Dim cOperatorler As String = Operatorler(New Random().Next(0, Operatorler.Length))
Select Case cOperatorler
Case "+"
Cevap = Sayi1 + Sayi2
If Cevap <= 0 Then GoTo Baslangic
Case "-"
Cevap = Sayi1 - Sayi2
If Cevap <= 0 Then GoTo Baslangic
End Select
Return String.Format("{0}{1}{2}", Sayi1, cOperatorler, Sayi2)
End Function
Private Sub CizgiOlustur(ByVal G As Graphics)
If Not G Is Nothing Then
Dim R As New Random()
Dim RenkFirca As New SolidBrush(Color.LightGray)
For i% = 0 To 9
G.DrawLines(New Pen(RenkFirca, R.Next(1, 2)), New Point() {New Point(0, R.Next(0, 60)), New Point(200, R.Next(0, 60))})
Next
End If
End Sub
Private Function ResimOlustur() As Image
Dim B As New Bitmap(200, 60)
Using G As Graphics = Graphics.FromImage(B)
With G
.Clear(Color.White)
.DrawString(KodOlustur(), New Font("Segoe UI", 20), Brushes.Black, New Rectangle(0, 0, 200, 60), New StringFormat() With {.Alignment = StringAlignment.Center, .LineAlignment = StringAlignment.Center})
End With
CizgiOlustur(G)
End Using
Return B
End Function