[العواد الصغير]

ضع هذا الكود   داخل الفورم 
بالتوفيق
  Private Sub RadioButton1_CheckedChanged(sender As Object, e As EventArgs) Handles RadioButton1.CheckedChanged

        ComboBox1.DisplayMember = "namee"
        ComboBox1.ValueMember = "namee"
    End Sub

    Private Sub RadioButton2_CheckedChanged(sender As Object, e As EventArgs) Handles RadioButton2.CheckedChanged
        ComboBox1.DisplayMember = "jans"
        ComboBox1.ValueMember = "jans"
    End Sub