Presuming you're not in the Royal Enclosure then this is the Grandstand dress code:
Grandstand Admission Dress Code Ladies with a Grandstand Admission ticket are required to dress in a manner appropriate to a smart occasion. Many wear hats although this is not compulsory. Gentlemen in the Grandstand Admission area must wear a shirt and tie, preferably with a suit or jacket. Sports attire, jeans and shorts are strictly forbidden.
This is the Royal Enclosure one!
Royal Enclosure Dress Code Her Majestys Representative wishes to point out that only formal day dress with a hat or substantial fascinator will be acceptable. Off the shoulder, halter neck, spaghetti straps and dresses with a strap of less than one inch and miniskirts are considered unsuitable. Midriffs must be covered and trouser suits must be full length and of matching material and colour.
i think something like that ( in the print you mentioned ) would look very nice. if you look at the ascot pictures, most ladies wear prom-style dresses or (depending on age) matching 2 piece suits ( Mother of bride - jacques vert style)
Its in a box so i dont know, weve just been told smart, suit for dh and dress for me hat optionsl. Do they have hospitality boxes in both the grandstand and the royal enclosure? I very much doubt its the royal one, its a construction business ticket
I went last year (not in Royal enclosure) and to be honest with you there was a whole range of what people wore, some amazing hats but a lot of people without a hat and there were even people in maxi dresses and flat shoes.
I think your dress will be fine, it can be quite breezy so I would take something in case you get chilly and make sure your shoes are comfy as it is quite a walk from the train station, I had a pair of flip flops in my hand bag which I am ashamed to say I had to put on at the end of the day to walk back to the train station!
Although I like it, I personally wouldn't wear that dress to the races as it's too bridesmaid-esque. I prefer shift style day dresses. But ppl wear anything and everything so you will be fine. I like the fascinator you linked to.