Protected Overrides Sub OnLoad(ByVal e As System.EventArgs)
        Dim Rnd As New System.Random
        Dim l1 As Integer
        Dim l2 As Integer = 0
        Me.Controls.AddRange(New Control() {dgv})
        With (dt.Columns)
            .Add("Zahl1", GetType(Integer))
            .Add("Zahl2", GetType(Integer))
            .Add("Eingabe", GetType(Integer))
            .Add("Ergebniss", GetType(Integer))
            .Add("richtig", GetType(Integer))
            .Add("falsch", GetType(Integer))
        End With
        If IO.File.Exists(DatasetName) Then dt.ReadXml(DatasetName)
        For i As Integer = 1 To 10
z_z:
            Dim zz As Integer
            zz = Rnd.Next(-2, +2)
            If zz = 0 Then GoTo z_z
s_1:
            s1 = Rnd.Next(10000, 100000000)
            If InStr(s1 / 2, ",") > 0 Then GoTo s_1
 
            s2 = Rnd.Next(100, 9999)
s_2:
            s1 = s1 + zz
            eg = s1 / s2
            If InStr(eg / 2, ",") > 0 Then GoTo s_2
            Dim lb0 As New Label
            l1 = 0
            Me.Controls.Add(lb0)
            lb0.Name = "Zahl1_" & CStr(i)
            lb0.Left = 20
            l2 = l2 + 20
            lb0.Top = l2
            lb0.Width = 60
            lb0.Height = 15
            lb0.Text = s1
            lb0.TextAlign = ContentAlignment.MiddleRight
            lb0.Visible = True
            mylabelBoxes.Add(lb0.Name, lb0)
            Dim lb1 As New Label
            l1 = 1
            Me.Controls.Add(lb1)
            lb1.Name = "rechenart_" & CStr(i)
            lb1.Left = 80
            lb1.Top = l2
            lb1.Width = 15
            lb1.Height = 15
            lb1.Text = ":"
            lb1.TextAlign = ContentAlignment.MiddleCenter
            lb1.Visible = True
            mylabelBoxes.Add(lb1.Name, lb1)
            Dim lb2 As New Label
            l1 = 2
            Me.Controls.Add(lb2)
            lb2.Name = "zahl2_" & CStr(i)
            lb2.Left = 95
            lb2.Top = l2
            lb2.Width = 50
            lb2.Height = 15
            lb2.Text = s2
            lb2.TextAlign = ContentAlignment.MiddleRight
            lb2.Visible = True
            mylabelBoxes.Add(lb2.Name, lb2)
            Dim lb3 As New Label
            l1 = 3
            Me.Controls.Add(lb3)
            lb3.Name = "gleich_" & CStr(i)
            lb3.Left = 145
            lb3.Top = l2
            lb3.Width = 15
            lb3.Height = 15
            lb3.Text = "="
            lb3.TextAlign = ContentAlignment.MiddleCenter
            lb3.Visible = True
            mylabelBoxes.Add(lb3.Name, lb3)
            l1 = 4
            Dim tx4 As New TextBox
            Me.Controls.Add(tx4)
            tx4.Name = "Ergebnis_" & CStr(i)  'eindeutiger Name
            tx4.Left = 160
            tx4.Top = l2
            tx4.Width = 80
            tx4.Height = 15
            tx4.BorderStyle = BorderStyle.None
            tx4.BackColor = System.Drawing.SystemColors.Control
            tx4.Text = "ertghff_" & CStr(i) 'zum Test gefüllt
            tx4.TextAlign = HorizontalAlignment.Right
            tx4.Visible = True
            mytextBoxes.Add(tx4.Name, tx4)
            AddEntry(s1, s2, lö, eg, 0, 0)
        Next
        Dim but As New Button
        Me.Controls.Add(but)
        but.Text = "Prüfen"
        but.Left = 30
        but.Width = 50
        but.Height = 20
        but.Top = mytextBoxes("Ergebnis_10").Top + 30
        AddHandler but.Click, AddressOf but_click
        dgv.Visible = False
    End Sub