implant mvvm

MyFirstMauiApp/NotesNet8/Models/Note.cs

@@ -11,5 +11,46 @@ namespace NotesNet8.Models
         public string Filename { get; set; }
         public string Text { get; set; }
         public DateTime Date { get; set; }
+
+        public Note()
+        {
+            Filename = $"{Path.GetRandomFileName()}.notes.txt";
+            Date = DateTime.Now;
+            Text = "";
+        }
+
+        public static Note Load(string filename)
+        {
+            filename = Path.Combine(FileSystem.AppDataDirectory, filename);
+            if (!File.Exists(filename))
+                throw new FileNotFoundException("Unable to find file on local storage.", filename);
+
+            return new Note()
+            {
+                Filename = Path.GetFileName(filename),
+                Text = File.ReadAllText(filename),
+                Date = File.GetLastWriteTime(filename)
+            };
+        }
+
+        public static IEnumerable<Note> LoadAll()
+        {
+            string appDataPath = FileSystem.AppDataDirectory;
+
+            return Directory
+                .EnumerateFiles(appDataPath, "*.notes.txt")
+                .Select(filename => Note.Load(Path.GetFileName(filename)))
+                .OrderByDescending(note => note.Date);
+        }
+
+        public void Save()
+        {
+            File.WriteAllText(Path.Combine(FileSystem.AppDataDirectory, Filename), Text);
+        }
+
+        public void Delete()
+        {
+            File.Delete(Path.Combine(FileSystem.AppDataDirectory, Filename));
+        }
     }
 }

MyFirstMauiApp/NotesNet8/NotesNet8.csproj

@@ -62,6 +62,7 @@
 	</ItemGroup>
 
 	<ItemGroup>
+		<PackageReference Include="CommunityToolkit.Mvvm" Version="8.2.2" />
 		<PackageReference Include="Microsoft.Maui.Controls" Version="$(MauiVersion)" />
 		<PackageReference Include="Microsoft.Maui.Controls.Compatibility" Version="$(MauiVersion)" />
 		<PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="8.0.0" />

MyFirstMauiApp/NotesNet8/ViewModels/AboutViewModel.cs

@@ -0,0 +1,26 @@
+using CommunityToolkit.Mvvm.Input;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+namespace NotesNet8.ViewModels
+{
+    internal class AboutViewModel
+    {
+        public string Title => AppInfo.Name;
+        public string Version => AppInfo.VersionString;
+        public string MoreInfoUrl => "https://aka.ms/maui";
+        public string Message => "This app is written in XAML and C# with .NET MAUI";
+        public ICommand ShowMoreInfoCommand { get; }
+
+        public AboutViewModel()
+        {
+            ShowMoreInfoCommand = new AsyncRelayCommand(ShowMoreInfo);
+        }
+
+        async Task ShowMoreInfo() => await Launcher.Default.OpenAsync(MoreInfoUrl);
+    }
+}

MyFirstMauiApp/NotesNet8/ViewModels/NoteViewModel.cs

@@ -0,0 +1,86 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using NotesNet8.Models;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+namespace NotesNet8.ViewModels
+{
+    internal class NoteViewModel : ObservableObject, IQueryAttributable
+    {
+        private Note _note;
+
+        public NoteViewModel()
+        {
+            _note = new Note();
+            SaveCommand = new AsyncRelayCommand(Save);
+            DeleteCommand = new AsyncRelayCommand(Delete);
+        }
+
+        public NoteViewModel(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 ICommand SaveCommand { get; private set; }
+        public ICommand DeleteCommand { get; private set; }
+
+        public DateTime Date => _note.Date;
+
+        public string Identifier => _note.Filename;
+
+        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}");
+        }
+
+        public void ApplyQueryAttributes(IDictionary<string, object> query)
+        {
+            if (query.ContainsKey("load"))
+            {
+                _note = Note.Load(query["load"].ToString());
+                RefreshProperties();
+            }
+        }
+
+        public void Reload()
+        {
+            _note = Note.Load(_note.Filename);
+            RefreshProperties();
+        }
+
+        private void RefreshProperties()
+        {
+            OnPropertyChanged(nameof(Text));
+            OnPropertyChanged(nameof(Date));
+        }
+    }
+}

MyFirstMauiApp/NotesNet8/ViewModels/NotesViewModel.cs

@@ -0,0 +1,60 @@
+using CommunityToolkit.Mvvm.Input;
+using NotesNet8.Models;
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Input;
+
+namespace NotesNet8.ViewModels
+{
+    internal class NotesViewModel : IQueryAttributable
+    {
+        public ObservableCollection<NoteViewModel> AllNotes { get; }
+        public ICommand NewCommand { get; }
+        public ICommand SelectNoteCommand { get; }
+
+        public NotesViewModel()
+        {
+            AllNotes = new ObservableCollection<NoteViewModel>(Note.LoadAll().Select(n => new NoteViewModel(n)));
+            NewCommand = new AsyncRelayCommand(NewNoteAsync);
+            SelectNoteCommand = new AsyncRelayCommand<NoteViewModel>(SelectNoteAsync);
+        }
+
+        public void ApplyQueryAttributes(IDictionary<string, object> query)
+        {
+            if (query.ContainsKey("deleted"))
+            {
+                string noteId = query["deleted"].ToString();
+                NoteViewModel matchedNote = AllNotes.Where(n => n.Identifier == noteId).FirstOrDefault();
+                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 (matchedNote != null)
+                {
+                    matchedNote.Reload();
+                    AllNotes.Move(AllNotes.IndexOf(matchedNote), 0);
+                }
+                else
+                    AllNotes.Insert(0, new NoteViewModel(Note.Load(noteId)));
+            }
+        }
+
+        private async Task NewNoteAsync()
+        {
+            await Shell.Current.GoToAsync(nameof(Views.NotePage));
+        }
+
+        private async Task SelectNoteAsync(ViewModels.NoteViewModel note)
+        {
+            if (note != null)
+                await Shell.Current.GoToAsync($"{nameof(Views.NotePage)}?load={note.Identifier}");
+        }
+    }
+}

MyFirstMauiApp/NotesNet8/Views/AboutPage.xaml

@@ -2,10 +2,10 @@
 <ContentPage x:Class="NotesNet8.Views.AboutPage"
              xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
-             xmlns:models="clr-namespace:NotesNet8.Models"
+             xmlns:viewModels="clr-namespace:NotesNet8.ViewModels"
              Title="AboutPage">
     <ContentPage.BindingContext>
-        <models:About />
+        <viewModels:AboutViewModel />
     </ContentPage.BindingContext>
 
     <VerticalStackLayout Margin="10" Spacing="10">
@@ -20,6 +20,6 @@
         </HorizontalStackLayout>
 
         <Label Text="{Binding Message}" />
-        <Button Clicked="LearnMore_Clicked" Text="Learn more..." />
+        <Button Command="{Binding ShowMoreInfoCommand}" Text="Learn more..." />
     </VerticalStackLayout>
 </ContentPage>

MyFirstMauiApp/NotesNet8/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)
-        {
-            await Launcher.Default.OpenAsync(about.MoreInfoUrl);
-        }
-    }
 }

MyFirstMauiApp/NotesNet8/Views/AllNotesPage.xaml

@@ -2,23 +2,27 @@
 <ContentPage x:Class="NotesNet8.Views.AllNotesPage"
              xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
-             xmlns:models="clr-namespace:NotesNet8.Models"
+             xmlns:viewModels="clr-namespace:NotesNet8.ViewModels"
-             Title="AllNotesPage">
+             Title="AllNotesPage"
+             NavigatedTo="ContentPage_NavigatedTo">
+    <ContentPage.BindingContext>
+        <viewModels:NotesViewModel />
+    </ContentPage.BindingContext>
+
     <ContentPage.ToolbarItems>
-        <ToolbarItem Clicked="Add_Clicked"
+        <ToolbarItem Command="{Binding NewCommand}"
                      IconImageSource="{FontImage Glyph='+',
                                                  Color=Black,
                                                  Size=22}"
                      Text="Add" />
     </ContentPage.ToolbarItems>
-    <ContentPage.BindingContext>
-        <models:AllNotes />
-    </ContentPage.BindingContext>
 
     <CollectionView x:Name="notesCollection"
                     Margin="20"
-                    ItemsSource="{Binding Notes}"
+                    ItemsSource="{Binding AllNotes}"
-                    SelectionChanged="notesCollection_SelectionChanged" SelectionMode="Single">
+                    SelectionMode="Single"
+                    SelectionChangedCommand="{Binding SelectNoteCommand}"
+                    SelectionChangedCommandParameter="{Binding Source={RelativeSource Self}, Path=SelectedItem}">
         <CollectionView.ItemsLayout>
             <LinearItemsLayout ItemSpacing="10" Orientation="Vertical" />
         </CollectionView.ItemsLayout>

MyFirstMauiApp/NotesNet8/Views/AllNotesPage.xaml.cs

@@ -5,30 +5,10 @@ public partial class AllNotesPage : ContentPage
 	public AllNotesPage()
 	{
 		InitializeComponent();
-
-        BindingContext = new Models.AllNotes();
-	}
-
-    protected override void OnAppearing()
-    {
-        base.OnAppearing();
-
-        ((Models.AllNotes)BindingContext).LoadNotes();
 	}
 
-    private async void Add_Clicked(object sender, EventArgs e)
+    private void ContentPage_NavigatedTo(object sender, NavigatedToEventArgs e)
     {
-        await Shell.Current.GoToAsync(nameof(NotePage));
-    }
-
-    private async void notesCollection_SelectionChanged(object sender, SelectionChangedEventArgs e)
-    {
-        if (e.CurrentSelection.Count == 0)
-            return;
-
-        var note = (Models.Note)e.CurrentSelection[0];
-        await Shell.Current.GoToAsync($"{nameof(NotePage)}?{nameof(NotePage.ItemId)}={note.Filename}");
-
 		notesCollection.SelectedItem = null;
     }
 }

MyFirstMauiApp/NotesNet8/Views/NotePage.xaml

@@ -2,10 +2,10 @@
 <ContentPage x:Class="NotesNet8.Views.NotePage"
              xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
-             xmlns:models="clr-namespace:NotesNet8.Models"
+             xmlns:viewModels="clr-namespace:NotesNet8.ViewModels"
              Title="NotePage">
     <ContentPage.BindingContext>
-        <models:Note />
+        <viewModels:NoteViewModel />
     </ContentPage.BindingContext>
 
     <VerticalStackLayout Margin="5" Spacing="10">
@@ -14,9 +14,11 @@
                 Text="{Binding Text}" />
         <Grid ColumnDefinitions="*,*" ColumnSpacing="4">
             <Button Grid.Column="0"
-                    Clicked="SaveButton_Clicked" Text="Save" />
+                    Command="{Binding SaveCommand}"
+                    Text="Save" />
             <Button Grid.Column="1"
-                    Clicked="DeleteButton_Clicked" Text="Delete" />
+                    Command="{Binding DeleteCommand}"
+                    Text="Delete" />
         </Grid>
     </VerticalStackLayout>
 </ContentPage>

MyFirstMauiApp/NotesNet8/Views/NotePage.xaml.cs

@@ -1,50 +1,9 @@
 namespace NotesNet8.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 void LoadNote(string fileName)
-    {
-        Models.Note noteModel = new Models.Note();
-        noteModel.Filename = fileName;
-
-        if (File.Exists(fileName))
-        {
-            noteModel.Date = File.GetCreationTime(fileName);
-            noteModel.Text = File.ReadAllText(fileName);
-        }
-
-        BindingContext = noteModel;
-    }
-
-    private async void SaveButton_Clicked(object sender, EventArgs e)
-    {
-        if (BindingContext is Models.Note note)
-            File.WriteAllText(note.Filename, TextEditor.Text);
-
-        await Shell.Current.GoToAsync("..");
-    }
-
-    private async void DeleteButton_Clicked(object sender, EventArgs e)
-    {
-        if (BindingContext is Models.Note note)
-        {
-            if (File.Exists(note.Filename))
-                File.Delete(note.Filename);
-        }
-
-        await Shell.Current.GoToAsync("..");
     }
 }