evaluateUserEntries VB.NET

Public Class Form1


    Private Sub TextBox_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles TextBox2.TextChanged, TextBox1.TextChanged

        evaluateUserEntries()
    End Sub

    Private Sub ComboBox1_SelectedValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedValueChanged
        evaluateUserEntries()
    End Sub
    Private Sub evaluateUserEntries() Handles RadioButton1.CheckedChanged, RadioButton2.CheckedChanged

        Dim rButton As RadioButton = GroupBox1.Controls.OfType(Of RadioButton)().Where(Function(r) r.Checked = True).FirstOrDefault()
        Button1.Enabled = TextBox1.Text <> "" And TextBox2.Text <> "" And ComboBox1.SelectedIndex <> -1 And IsNothing(rButton) = False

    End Sub

End Class