All dalmatians have a metabolic defect which makes urate stone-forming a possibility. Nobody knows why some will form stones and others, even littermates fed the same diet, will be symptom-free their entire lives. What is known is that foods containing high-purine proteins (offal, game, oily fish, broccoli, spinach, beef) increase the risk so these should be avoided. Protein sources should be those with lower purine levels - white fish and chicken have medium levels, so some can be given, but eggs and dairy products have low levels and are the safest - if the individual dog isn't intolerant to them, of course!
Dogs are at a greater risk from stones than bitches due to their anatomy. In dogs the narrow urethra passes through the os penis, preventing stones larger than about 3mm in diameter passing through, causing a urinary obstruction which, if left untreated, will cause the painful death of the animal with days. The urethra in bitches is not only wider anyway, but only passes therough soft tissue so can expand to a certain extent to allow the passage of stones which would obstruct a male. That said, bitches can and do obstruct if the stone has become quite large, so there's no room for complacency. Stones can also form in the kidney rather than the bladder, and cause a different set of problems.
There's a very good brief explanation of general stone-forming
here, with further links to detailed studies and lists of foods and ingredients which owners of dals in particular should avoid feeding their dogs.
What seems to be a very important factor in avoiding stones is ensuring that dogs drink plenty to keep the urine plentiful and dilute - a 20kg dog should have about a litre of fluid daily - and plenty of opportunity to urinate, about every three hours. The situation which puts them most at risk as being fed dried food dry rather than wetted, then being left all day while the owners are out of the house. These conditions are ideal for developing this serious condition.
Lots of information about the other forms of stones and their treatment
here. All breeds are at risk from certain types of stones, so it's useful reading for all owners.