RadDropDownList uses different popups for its default items representation and for its auto complete suggest items. Here is an example demonstrating how to change the font of both:
void radGridView1_CellEditorInitialized(object sender, GridViewCellEventArgs e)
{
RadDropDownListEditor editor = e.ActiveEditor as RadDropDownListEditor;
if (editor != null)
{
editor.DropDownStyle = RadDropDownStyle.DropDown;
RadDropDownListEditorElement element = (RadDropDownListEditorElement)editor.EditorElement;
element.VisualItemFormatting -= element_VisualItemFormatting;
element.AutoCompleteSuggest.DropDownList.VisualItemFormatting -= element_VisualItemFormatting;
//this handles the default drop down formatting - when you press the arrow key to open the drop down
element.VisualItemFormatting += element_VisualItemFormatting;
//this handles the suggest popup formatting
element.AutoCompleteSuggest.DropDownList.VisualItemFormatting += element_VisualItemFormatting;
}
}
void element_VisualItemFormatting(object sender, VisualItemFormattingEventArgs args)
{
args.VisualItem.Font = new Font("Arial", 16);
}