Problem in calling the data base

I have followed the article (link in the question), added the code and the button click handlers. The SQLite installation details are incorrect so I had to install the correct package and change the code to reflect that.

My tests run to completion but do nothing apart from creating the database. I then added the code to insert some student records and that also works correctly. I was only able to verify the success by running the sqlite3 program from a terminal window.

So for someone with very little knowledge of UWP, .NET and C# This article will not really help, as there are too many things in it which are wrong and/or missing.

[edit]
Adding a working solution based (loosely) on the original article.

1. Create a new UWP Blank page application in Visual Studio.
2. Replace the content of MainPage.xaml and MainPage.xaml.cs with the relevant parts below.
3. Add a new class named Students, and replace the text with the content of Students.cs below.
4. From the Visual Studio menu tabs Select Tools -> Nuget Package Manager -> Manage Nuget Packages for Solution.
5. Use the "Browse" tab and search for "SQLite.Core.UAP" and install it to the project.
6. Search for "sqlite-net-pcl" and install that to the project.

If you have done that all correctly it should now build and you can run it by clicking <Ctrl+F5>.

MainPage.xaml

<Page
    x:Class="Students.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:Students"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <Page.Resources>
        <Style x:Name="ColumnItemBorder" TargetType="Border">
            <Setter Property="BorderBrush" Value="Gray" />
            <Setter Property="BorderThickness" Value="1" />
            <Setter Property="Margin" Value="5, 0, 5, 0" />
        </Style>
    </Page.Resources>
    <Grid Margin="5, 15, 5, 5">
        <Grid.ColumnDefinitions>
            <ColumnDefinition></ColumnDefinition>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <CommandBar  Grid.Row="0">
            <AppBarButton x:Name="init" Icon="NewWindow" Label="New" ToolTipService.ToolTip="Initialize" Click="create_Click"/>
            <AppBarButton x:Name="add" Icon="Add" Label="Add" ToolTipService.ToolTip="Add" Click="insert_Click" />
            <AppBarButton x:Name="read" Icon="ViewAll" ToolTipService.ToolTip="View all" Label="Read All" Click="read_Click"/>
            <AppBarButton x:Name="update" Icon="Edit" ToolTipService.ToolTip="Update" Label="Update" Click="update_Click" />
        </CommandBar>
        <ListView x:Name="allstudents" HorizontalAlignment="Stretch" Grid.Row="1">
            <ListView.HeaderTemplate>
                <DataTemplate>
                    <Grid>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="*" />
                        </Grid.RowDefinitions>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="30" />
                            <ColumnDefinition Width="100" />
                            <ColumnDefinition Width="120" />
                            <ColumnDefinition Width="120" />
                        </Grid.ColumnDefinitions>
                        <TextBlock Margin="15 0 0 0" Grid.Row="0" Grid.Column="0" Foreground="#ff0000" Text="Id"  />
                        <TextBlock Margin="15 0 15 0" Grid.Row="0" Grid.Column="1" Foreground="#ff0000" Text="Name" />
                        <TextBlock Margin="15 0 15 0" Grid.Row="0" Grid.Column="2" Foreground="#ff0000" Text="Address" />
                        <TextBlock Margin="15 0 15 0" Grid.Row="0" Grid.Column="3" Foreground="#ff0000" Text="Mobile" />
                    </Grid>
                </DataTemplate>
            </ListView.HeaderTemplate>
            <ListView.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="*" />
                        </Grid.RowDefinitions>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="30" />
                            <ColumnDefinition Width="100" />
                            <ColumnDefinition Width="120" />
                            <ColumnDefinition Width="120" />
                        </Grid.ColumnDefinitions>
                        <TextBlock Margin="7 0 0 0"  Grid.Row="0" Grid.Column="0" Foreground="DarkBlue" Text="{Binding Id}"/>
                        <TextBlock Margin="7 0 15 0" Grid.Row="0" Grid.Column="1" Foreground="DarkBlue" Text="{Binding Name}" />
                        <TextBlock Margin="7 0 15 0" Grid.Row="0" Grid.Column="2" Foreground="DarkBlue" Text="{Binding Address}" />
                        <TextBlock Margin="7 0 15 0" Grid.Row="0" Grid.Column="3" Foreground="DarkBlue" Text="{Binding Mobile}" />
                    </Grid>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </Grid>
</Page>

MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using System.Net;
using System.Reflection;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Xml.Linq;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace Students
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        Students students;
        string dbname = "Studentdb.sqlite";
        public MainPage()
        {
            this.InitializeComponent();
            students = new Students();
        }

        private void create_Click(object sender, RoutedEventArgs e)
        {
            students.Initialize(dbname, true);
        }

        private void insert_Click(object sender, RoutedEventArgs e)
        {
            Student[] newstudents = {
                new Student("Harold", "LONDON", "07966-513229"),
                new Student("Sadie", "GLASGOW", "07981-277438"),
                new Student("David", "NEW YORK", "+1-431-7438"),
                new Student("Aristotle", "ATHENS", "+30-21-1234567"),
                new Student("Carlo", "ROME", "+39-3987654321")
            };
            foreach (Student student in newstudents)
            {
                students.Add(student);
            }
        }
        private void read_Click(object sender, RoutedEventArgs e)
        {
            List<Student> studentlist = students.ReadAll();
            ObservableCollection<Student> studentCollection = new ObservableCollection<Student>(studentlist);
            allstudents.BorderThickness = new Thickness(3);
            allstudents.BorderBrush = new Windows.UI.Xaml.Media.SolidColorBrush(Windows.UI.Colors.Black);
            allstudents.ItemsSource = studentCollection;
        }

        private void update_Click(object sender, RoutedEventArgs e)
        {
            students.Update(3, null, "LOS ANGELES", "+1-345-7811");
        }
    }
}

Students.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.UI.Xaml;

namespace Students
{
    internal class Students
    {
        string sqlpath = System.IO.Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, "Studentdb.sqlite");

        public Students()
        {
        }

        public void Initialize(string database, bool create = false)
        {
            sqlpath = System.IO.Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, database);
            if (create)
            {
                using (SQLite.SQLiteConnection connection = new SQLite.SQLiteConnection(sqlpath))
                {
                    connection.DropTable<Student>();
                    connection.CreateTable<Student>();
                }
            }
        }

        public void Add(Student student)
        {
            using (SQLite.SQLiteConnection connection = new SQLite.SQLiteConnection(sqlpath))
            {
                connection.RunInTransaction(() =>
                {
                    connection.Insert(student);
                });
            }
        }

        public void Update(int studentid, string name, string address, string mobile)
        {
            using (SQLite.SQLiteConnection connection = new SQLite.SQLiteConnection(sqlpath))
            {
                var existingstudent = connection.Query<Student>("SELECT * FROM Student WHERE Id =\"" + studentid + "\"").FirstOrDefault();
                if (existingstudent != null)
                {
                    if (name != null)
                        existingstudent.Name = name;
                    if (address != null)
                        existingstudent.Address = address;
                    if (mobile != null)
                        existingstudent.Mobile = mobile;
                    connection.RunInTransaction(() =>
                    {
                        connection.Update(existingstudent);
                    });
                }
            }
        }

        // Retrieve the specific contact from the database.    
        public Student Read(int studentid)
        {
            using (SQLite.SQLiteConnection connection = new SQLite.SQLiteConnection(sqlpath))
            {
                var existingstudent = connection.Query<Student>("SELECT * FROM Student WHERE Id =" + studentid).FirstOrDefault();
                return existingstudent;
            }
        }

        public List<Student> ReadAll()
        {
            List<Student> studentList = null;
            using (SQLite.SQLiteConnection connection = new SQLite.SQLiteConnection(sqlpath))
            {
                studentList = connection.Table<Student>().ToList<Student>();
            }
            return studentList;
        }

        public void DeleteContact(int Id)
        {
            using (SQLite.SQLiteConnection connection = new SQLite.SQLiteConnection(sqlpath))
            {
                var existingstudent = Read(Id);
                if (existingstudent != null)
                {
                    connection.RunInTransaction(() =>
                    {
                        connection.Delete(existingstudent);
                    });
                }
            }
        }
    }

    internal class Student
    {
        [SQLite.PrimaryKey, SQLite.AutoIncrement]
        public int Id
        {
            get;
            set;
        }
        public string Name
        {
            get;
            set;
        }
        public string Address
        {
            get;
            set;
        }
        public string Mobile
        {
            get;
            set;
        }
        public Student()
        { }
        public Student(string name, string address, string mobile)
        {
            Name = name;
            Address = address;
            Mobile = mobile;
        }
    }
}

[edit]