Is there any way to change the background color of the ComboBox control with DropDownList in Windows Forms

Is there any way to change the background color of the ComboBox control with DropDownStyle = DropDownList in Windows Forms?

If I just do

this.comboBox.BackColor = Color.Red;

nothing changed.

I need to highlight this ComboBox when the user doesn't choose any item (I can't provide the default item in my case).

Thanks in advance.