c# - collection view lazy loading in code behind Not MVVM [Xamarin forms]

Question

Did anyone try to implement a lazy loading feature for Collection View Control using the code Behind not the MVVM architecture? I have a group of items that sometimes reach 2000 items with pictures, I need to display 20 items and when going to the bottom of the page, another 20 are displayed !! There are many explanations all in MVVM style, I need help using Behind code

        var CategutyRespons = await httpclint.GetAsync(URL + "/Categuty");
        if (CategutyRespons.StatusCode == System.Net.HttpStatusCode.OK)
        {
            var jsonResponse = await CategutyRespons.Content.ReadAsStringAsync();
            var CategutysList = JsonConvert.DeserializeObject<StartDataClass>(jsonResponse);
            //Binding Data to CollectionView 
            Category.ItemsSource = CategutysList.Categories.OrderBy(x => Guid.NewGuid());
        }

Answer 1

等待大神解答