For using the PieChart, that is very easy, you just need to bind the series collection

Then I just need to get the data from my repo:

            var categories = new ObservableCollection(_database.BudgetCategories.GetAllCategories());

            SeriesCollection = new SeriesCollection();
            foreach (var category in categories)
            {
                var budgetItems = new ObservableCollection(_database.BudgetItems.GetItemByCategory(category));
                double amount = 0;
                foreach (var item in budgetItems)
                {
                    amount += (double) item.Amount;
                }
                var pieSeries = new PieSeries
                {
                    Title = category.Name,
                    Values = new ChartValues { new ObservableValue(amount) },
                    DataLabels = true
                };
                SeriesCollection.Add(pieSeries);
            }
         
        }