void ComboBox_DropDownStyleChanged (object sender, EventArgs e)
{
_dropDownRadioButton.Checked = _comboBox.DropDownStyle == ComboBoxStyle.DropDown;
_dropDownListRadioButton.Checked = _comboBox.DropDownStyle == ComboBoxStyle.DropDownList;
_simpleRadioButton.Checked = _comboBox.DropDownStyle == ComboBoxStyle.Simple;
}