Public Class frmSettingsDialog
 
    'Membervariable 
    Private Property _TB_Tabindex As Integer
    'Per Code erstellte Controls
    Private WithEvents txtTabindex As New TextBox _
         With {.Parent = Me, .Top = 10, .Left = 10, .Width = 100}
 
    Private WithEvents btnOk As New Button With _
        {.Parent = Me, .Top = 40, .Left = 10, .Text = "OK", _
         .DialogResult = DialogResult.OK}
 
    Private WithEvents btnCancel As New Button With _
        {.Parent = Me, .Top = 40, .Left = 100, .Text = "Cancel", _
         .DialogResult = DialogResult.Cancel}
 
    'Eigenschaft für Tabindex
    Public Property TB_Tabindex As Integer
        Set(ByVal value As Integer)
            _TB_Tabindex = value
            txtTabindex.Text = CStr(value)
        End Set
        Get
            Return _TB_Tabindex
        End Get
    End Property
 
    'Schließen des Formulars durch den User verhindern 
    Private Sub frmSettingsDialog_FormClosing(ByVal sender As Object, _
       ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles _
       Me.FormClosing
 
        If e.CloseReason = CloseReason.UserClosing Then
            Me.Hide()
            e.Cancel = True
        End If
    End Sub
 
    'Eingabe kontrollieren
    Private Sub txtTabindex_TextChanged(ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles txtTabindex.TextChanged
 
        If txtTabindex.Text <> String.Empty Then
            Dim index As Integer
            If Not Integer.TryParse(txtTabindex.Text.Trim, index) OrElse index _
              < 0 Then
                MsgBox("Unzulässige Eingabe")
            Else
                _TB_Tabindex = index
            End If
        End If
 
    End Sub
End Class

Public Class frmUser
 
    Dim mySettingsDialog As New frmSettingsDialog With _
      {.Owner = Me, .Visible = False}
    Dim WithEvents btnSettingsDialog As New Button With _
        {.Parent = Me, .Top = 10, .Left = 10, .Width = 100, .Text = "Settings"}
 
    Dim txtDemo As New TextBox With _
        {.Parent = Me, .Top = 40, .Left = 10, .Width = 300}
 
 
    Private Sub btnSettingsDialog_Click(ByVal sender As Object, _
       ByVal e As System.EventArgs) Handles btnSettingsDialog.Click
 
        With mySettingsDialog
            .TB_Tabindex = txtDemo.TabIndex
            If .ShowDialog = DialogResult.OK Then
                txtDemo.TabIndex = .TB_Tabindex
            End If
        End With
    End Sub
End Class