Xamarin Listview grouping

Question

I am dealing with a listview in xamarin.froms. I can easily populate the listview with a listitem for each record:

[
    {\"cat\":1, \"name\":\"alpha\"},
            


        

Answer 1

In my environment, the code was not work in this url http://motzcod.es/post/94643411707/enhancing-xamarinforms-listview-with-grouping .

The code that does not work is here

var partnersSorted = from item in Partners
         orderby item.UserName
         group item by item.UserNameSort into PartnersGroup
         select new Grouping(PartnersGroup.Key, PartnersGroup);

MonkeysGrouped = new ObservableCollection>(partnersSorted);

So I changed the code.

var sortedPartners = Partners.OrderBy(x => x.UserName).GroupBy(y => y.UserNameSort);
foreach (var item in sortedPartners)
{
     PartnersGrouped.Add(new PartnersGrouping(item.Key, Partners.Where(x=>x.UserNameSort == item.Key)));
}

You can see like this.

[https://i.stack.imgur.com/BswPq.png][1]

here is my all scripts

Item is Partner

Item.cs

using System;

namespace NewHeats.Models
{
    public class Item
    {
        public string Id
        {
            get;
            set;
        }
        public string UserName
        {
            get;
            set;
        }
        public DateTime RegisterDate
        {
            get;
            set;
        }
        public string Field
        {
            get;
            set;
        }
        public string Password
        {
            get;
            set;
        }
        public int Heats
        {
            get;
            set;
        }
        public string UserNameSort
        {
             get
            {
                 if (string.IsNullOrWhiteSpace(UserName) || UserName.Length == 0)
                    return "?";

                 return UserName[0].ToString().ToUpper();
            }
        }
    }
 }

PartnersGrouping.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
namespace NewHeats.Models
{
    public class PartnersGrouping : ObservableCollection
    {
        public K Key { get; private set; }

        public PartnersGrouping(K key,IEnumerable items)
        {
            Key = key;
            foreach (var item in items)
            {
                this.Items.Add(item);
            }
        }
    }
}

PartnersViewModel.cs

using System;
using System.Windows.Input;
using System.ComponentModel;
using System.Collections.ObjectModel;
using Xamarin.Forms;
using NewHeats.Models;
using System.Threading.Tasks;
using System.Diagnostics;
using System.Linq;
using System.Diagnostics.Contracts;

namespace NewHeats.ViewModels
{
    public class PartnersViewModel : BaseViewModel
    {
        public Item Me
        {
            get;
            set;
        }
        public ObservableCollection Partners { get; set; }
        public ObservableCollection> PartnersGrouped { get; set; }
        public Item SelectedPartner { get; set; }
        public Command LoadPartnersCommand { get; set; }
        public PartnersViewModel()
        {
            Title = "Partners";
            Partners = new ObservableCollection();
            PartnersGrouped = new ObservableCollection>();
            LoadPartnersCommand = new Command(async() =>await ExecuteLoadPartnersCommand());
        }

        async Task ExecuteLoadPartnersCommand()
        {
            Contract.Ensures(Contract.Result() != null);
            if (IsBusy)
                return;
            IsBusy = true;
            try
            {
                Me = await MockUsrDataStore.GetItemAsync("naoto");                           
                Partners.Clear();
                var allfriends = await MockFriDataStore.GetItemsAsync(true);                 
                var myFriends = allfriends.Where(x => x.MyId == Me.Id);                      
                var allUsers = await MockUsrDataStore.GetItemsAsync(true);                   

                foreach (var item in myFriends)
                {
                    var partner = allUsers.FirstOrDefault(x => x.Id == item.FriendId);       
                    if (partner!=null)
                    {
                        Partners.Add(partner);
                    }
                }
                var sortedpartners = Partners.OrderBy(x => x.UserName).GroupBy(y => y.UserNameSort);
                foreach (var item in sortedpartners)
                {
                     PartnersGrouped.Add(new PartnersGrouping(item.Key, Partners.Where(x=>x.UserNameSort == item.Key)));
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex);
            }
            finally
            {
                IsBusy = false;
            }
        }
    }
}

PartnerPage.xaml

    
        
            
            #2196F3
            #96d1ff
            #999999
        
    
    
        
            
        
        
            
                
                    
                        
                            
                                
                                       
                                
                            
                        
                    
                    
                        
                            
                                
                                    
                                        
                                    
                                    
                                        
                                        
                                    
                                    
                                    
                                       
                                           
                                      
                                
                            
                        
                    
                
            
        
    

Thanks!!