Xamarin ListView not displaying any data

I have a problem where I'm trying to display data inside a ListView in my app when binding a list of data to my ListView in XAML. The ListView does not populate with any data at all.

Here is all my coding:

My Code-behind

public ObservableCollection<RandomList> randomList = new ObservableCollection<RandomList>();

public App()
{
    MainPage = new MainUI();

    randomList.Add(new RandomList { Name = "Susan", Surname = "Potgieter", School = "Oosterlig" });
    randomList.Add(new RandomList { Name = "Jonathan", Surname = "Visagie", School = "Elspark" });
    randomList.Add(new RandomList { Name = "Gerhard", Surname = "Vermaak", School = "E.G. Jansen" });
    randomList.Add(new RandomList { Name = "Kobus", Surname = "Jacobs", School = "Oosterlig" });          
}

My XAML

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="RandomTest.MainUI">
  <StackLayout Padding="0,40,0,0">
    <Label Text="Hello" VerticalOptions="Center" HorizontalOptions="Center" />
    <Button x:Name="btnGetStudents" Text="Get Students"/>
    <ListView x:Name="lwStudents" ItemsSource="{Binding randomList}">
      <ListView.ItemTemplate>
        <DataTemplate>
          <TextCell Text="{Binding Name}" Detail="{Binding Surname}"/>
        </DataTemplate>
      </ListView.ItemTemplate> 
    </ListView>
  </StackLayout>
</ContentPage>

When I insert a breakpoint in my code behind where I add the dummy data to the list, I can then see in my XAML here: <ListView x:Name="lwStudents" ItemsSource="{Binding randomList}"> that there are 4 items in my randomList.

The problem is that there is no data in the two bindings below:

<TextCell Text="{Binding Name}" Detail="{Binding Surname}"/>

Can someone please tell or show me what I'm doing wrong in my binding? Or if you need ANY more info or code, please ask! I will be happy to give more info. :)

EDIT

I've updated my RandomList class and implemented INotifyPropertyChanged, but I still can't get my data to load in my ListView through XAML bindings.

using System.ComponentModel;

namespace RandomTest
{
    public class RandomList : INotifyPropertyChanged
    {
        public int Id { get; set; }

        string _name;
        public string Name
        {
            get { return _name; }
            set
            {
                if (_name != value)
                    _name = value;
                OnPropertyChanged("Name");
            }
        }

        string _surname;
        public string Surname
        {
            get { return _surname; }
            set
            {
                if (_surname != value)
                    _surname = value;
                OnPropertyChanged("Surname");
            }
        }

        string _school;
        public string School
        {
            get { return _school; }
            set
            {
                if (_school != value)
                    _school = value;
                OnPropertyChanged("School");
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

EDIT 2

This is how my MainUI.xaml.cs page looks like at the moment:

public partial class MainUI : ContentPage
{
    public MainUI()
    {
        InitializeComponent();
        BindingContext = new MainUIModel();

        MainUIModel mainUIModel = (MainUIModel)this.BindingContext;
        mainUIModel.randomList.Add(new RandomList { Name = "Susan", Surname = "Potgieter", School = "Oosterlig" });
        mainUIModel.randomList.Add(new RandomList { Name = "Jonathan", Surname = "Visagie", School = "Elspark" });
        mainUIModel.randomList.Add(new RandomList { Name = "Gerhard", Surname = "Vermaak", School = "E.G. Jansen" });
        mainUIModel.randomList.Add(new RandomList { Name = "Kobus", Surname = "Jacobs", School = "Oosterlig" });
    }
}