Add one event handler for DrawItem
this.ComboBox1 = new ComboBox();
this.ComboBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable;
this.ComboBox1.DrawItem += new DrawItemEventHandler(ComboBox1_DrawItem);
private void ComboBox1_DrawItem(object sender,
System.Windows.Forms.DrawItemEventArgs e)
{
}
There is a MSDN example here:
ComboBox.DrawItem