app converted to mvvm

MauiApp2/ViewModels/NoteViewModel.cs

@@ -1,12 +1,79 @@
-using System;
+using CommunityToolkit.Mvvm.ComponentModel;
-using System.Collections.Generic;
+using CommunityToolkit.Mvvm.Input;
-using System.Linq;
+using System.Windows.Input;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace MauiApp2.ViewModels
 {
-    class NoteViewModel
+    internal class NoteViewModel : ObservableObject, IQueryAttributable
     {
+        private Models.Note _note;
+
+        public NoteViewModel()
+        {
+            _note = new Models.Note();
+            SaveCommand = new AsyncRelayCommand(Save);
+            DeleteCommand = new AsyncRelayCommand(Delete);
+        }
+
+        public NoteViewModel(Models.Note note)
+        {
+            _note = note;
+            SaveCommand = new AsyncRelayCommand(Save);
+            DeleteCommand = new AsyncRelayCommand(Delete);
+        }
+
+        public string Text
+        {
+            get => _note.Text;
+            set
+            {
+                if (_note.Text != value)
+                {
+                    _note.Text = value;
+                    OnPropertyChanged();
+                }
+            }
+        }
+
+        public DateTime Date => _note.Date;
+
+        public string Identifier => _note.Filename;
+
+        public ICommand SaveCommand { get; private set; }
+        public ICommand DeleteCommand { get; private set; }
+
+        private async Task Save()
+        {
+            _note.Date = DateTime.Now;
+            _note.Save();
+            await Shell.Current.GoToAsync($"..?saved={_note.Filename}");
+        }
+
+        private async Task Delete()
+        {
+            _note.Delete();
+            await Shell.Current.GoToAsync($"..?deleted={_note.Filename}");
+        }
+
+        void IQueryAttributable.ApplyQueryAttributes(IDictionary<string, object> query)
+        {
+            if (query.ContainsKey("load"))
+            {
+                _note = Models.Note.Load(query["load"].ToString());
+                RefreshProperties();
+            }
+        }
+
+        public void Reload()
+        {
+            _note = Models.Note.Load(_note.Filename);
+            RefreshProperties();
+        }
+
+        private void RefreshProperties()
+        {
+            OnPropertyChanged(nameof(Text));
+            OnPropertyChanged(nameof(Date));
+        }
     }
 }

MauiApp2/ViewModels/NotesViewModel.cs

@@ -1,12 +1,56 @@
-using System;
+using CommunityToolkit.Mvvm.Input;
-using System.Collections.Generic;
+using MauiApp2.Models;
-using System.Linq;
+using System.Collections.ObjectModel;
-using System.Text;
+using System.Windows.Input;
-using System.Threading.Tasks;
 
 namespace MauiApp2.ViewModels
 {
-    class NotesViewModel
+    internal class NotesViewModel : IQueryAttributable
     {
+        public ObservableCollection<ViewModels.NoteViewModel> AllNotes { get; }
+        public ICommand NewCommand { get; }
+        public ICommand SelectNoteCommand { get; }
+        public NotesViewModel()
+        {
+            AllNotes = new ObservableCollection<ViewModels.NoteViewModel>(Models.Note.LoadAll().Select(n => new NoteViewModel(n)));
+            NewCommand = new AsyncRelayCommand(NewNoteAsync);
+            SelectNoteCommand = new AsyncRelayCommand<ViewModels.NoteViewModel>(SelectNoteAsync);
+        }
+
+        private async Task NewNoteAsync()
+        {
+            await Shell.Current.GoToAsync(nameof(Views.NotePage));
+        }
+
+        private async Task SelectNoteAsync(NoteViewModel note)
+        {
+            if (note != null)
+                await Shell.Current.GoToAsync($"{nameof(Views.NotePage)}?load={note.Identifier}");
+        }
+        void IQueryAttributable.ApplyQueryAttributes(IDictionary<string, object> query)
+        {
+            if (query.ContainsKey("deleted"))
+            {
+                string noteId = query["deleted"].ToString();
+                NoteViewModel matchedNote = AllNotes.Where((n) => n.Identifier == noteId).FirstOrDefault();
+
+                // If note exists, delete it
+                if (matchedNote != null)
+                    AllNotes.Remove(matchedNote);
+            }
+            else if (query.ContainsKey("saved"))
+            {
+                string noteId = query["saved"].ToString();
+                NoteViewModel matchedNote = AllNotes.Where((n) => n.Identifier == noteId).FirstOrDefault();
+
+                // If note is found, update it
+                if (matchedNote != null)
+                    matchedNote.Reload();
+
+                // If note isn't found, it's new; add it.
+                else
+                    AllNotes.Add(new NoteViewModel(Note.Load(noteId)));
+            }
+        }
     }
 }

MauiApp2/Views/AboutPage.xaml.cs

@@ -6,12 +6,4 @@ public partial class AboutPage : ContentPage
     {
         InitializeComponent();
     }
-    private async void LearnMore_Clicked(object sender, EventArgs e)
-    {
-        if (BindingContext is Models.About about)
-        {
-            // Navigate to the specified URL in the system browser.
-            await Launcher.Default.OpenAsync(about.MoreInfoUrl);
-        }
-    }
 }

MauiApp2/Views/AllNotesPage.xaml

@@ -2,19 +2,24 @@
 <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              x:Class="MauiApp2.Views.AllNotesPage"
-             
+             xmlns:viewModels="clr-namespace:MauiApp2.ViewModels"
              Title="Your Notes">
+    <ContentPage.BindingContext>
+        <viewModels:NotesViewModel />
+    </ContentPage.BindingContext>
+    
     <!-- Add an item to the toolbar -->
     <ContentPage.ToolbarItems>
-        <ToolbarItem Text="Add" Clicked="Add_Clicked" IconImageSource="{FontImage Glyph='+', Color=Black, Size=22}" />
+        <ToolbarItem Text="Add" Command="{Binding NewCommand}" IconImageSource="{FontImage Glyph='+', Color=Black, Size=22}" />
     </ContentPage.ToolbarItems>
 
     <!-- Display notes in a list -->
-    <CollectionView x:Name="notesCollection"
+   <CollectionView x:Name="notesCollection"
-                    ItemsSource="{Binding Notes}"
+                    ItemsSource="{Binding AllNotes}"
                     Margin="20"
                     SelectionMode="Single"
-                    SelectionChanged="notesCollection_SelectionChanged">
+                    SelectionChangedCommand="{Binding SelectNoteCommand}"
+                    SelectionChangedCommandParameter="{Binding Source={RelativeSource Self}, Path=SelectedItem}">
 
         <!-- Designate how the collection of items are laid out -->
         <CollectionView.ItemsLayout>

MauiApp2/Views/AllNotesPage.xaml.cs

@@ -1,38 +1,9 @@
-using MauiApp2.Models;
-
 namespace MauiApp2.Views;
 
 public partial class AllNotesPage : ContentPage
 {
-	public AllNotesPage()
+    public AllNotesPage()
-	{
-		InitializeComponent();
-
-        BindingContext = new AllNotes();
-    }
-
-    protected override void OnAppearing()
     {
-        ((AllNotes)BindingContext).LoadNotes();
+        InitializeComponent();
-    }
-
-    private async void Add_Clicked(object sender, EventArgs e)
-    {
-        await Shell.Current.GoToAsync(nameof(NotePage));
-    }
-
-    private async void notesCollection_SelectionChanged(object sender, SelectionChangedEventArgs e)
-    {
-        if (e.CurrentSelection.Count != 0)
-        {
-            // Get the note model
-            var note = (Note)e.CurrentSelection[0];
-
-            // Should navigate to "NotePage?ItemId=path\on\device\XYZ.notes.txt"
-            await Shell.Current.GoToAsync($"{nameof(NotePage)}?{nameof(NotePage.ItemId)}={note.Filename}");
-
-            // Unselect the UI
-            notesCollection.SelectedItem = null;
-        }
     }
 }

MauiApp2/Views/NotePage.xaml

@@ -2,7 +2,11 @@
 <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              x:Class="MauiApp2.Views.NotePage"
+             xmlns:viewModels="clr-namespace:MauiApp2.ViewModels"
              Title="NotePage">
+    <ContentPage.BindingContext>
+        <viewModels:NoteViewModel />
+    </ContentPage.BindingContext>
     <VerticalStackLayout Spacing="10" Margin="5">
         <Editor x:Name="TextEditor"
                 Text="{Binding Text}"
@@ -11,11 +15,13 @@
 
         <Grid ColumnDefinitions="*,*" ColumnSpacing="4">
             <Button Text="Save"
-                    Clicked="SaveButton_Clicked" />
+                    Command="{Binding SaveCommand}"/>
+
 
             <Button Grid.Column="1"
                     Text="Delete"
-                    Clicked="DeleteButton_Clicked" />
+                    Command="{Binding DeleteCommand}"/>
+
         </Grid>
     </VerticalStackLayout>
 </ContentPage>

MauiApp2/Views/NotePage.xaml.cs

@@ -1,55 +1,9 @@
-using MauiApp2.Models;
-
 namespace MauiApp2.Views;
 
-[QueryProperty(nameof(ItemId), nameof(ItemId))]
 public partial class NotePage : ContentPage
 {
-    public string ItemId
-    {
-        set => LoadNote(value);
-    }
-
     public NotePage()
-	{
-		InitializeComponent();
-
-        string appDataPath = FileSystem.AppDataDirectory;
-        string randomFileName = $"{Path.GetRandomFileName()}.notes.txt";
-
-        LoadNote(Path.Combine(appDataPath, randomFileName));
-    }
-
-    private async void SaveButton_Clicked(object sender, EventArgs e)
     {
-        if (BindingContext is Note note)
+        InitializeComponent();
-            File.WriteAllText(note.Filename, TextEditor.Text);
-
-        await Shell.Current.GoToAsync("..");
-    }
-
-    private async void DeleteButton_Clicked(object sender, EventArgs e)
-    {
-        if (BindingContext is Note note)
-        {
-            if (File.Exists(note.Filename))
-                File.Delete(note.Filename);
-        }
-
-        await Shell.Current.GoToAsync("..");
-    }
-
-    private void LoadNote(string fileName)
-    {
-        Note noteModel = new Note();
-        noteModel.Filename = fileName;
-
-        if (File.Exists(fileName))
-        {
-            noteModel.Date = File.GetCreationTime(fileName);
-            noteModel.Text = File.ReadAllText(fileName);
-        }
-
-        BindingContext = noteModel;
     }
 }