refactor: move Task creation from code behind to view model

Author: Xiphereal

Desktop/App.xaml.cs

@@ -1,5 +1,6 @@
 using System.Windows;
 using System.Windows.Threading;
+using Desktop.Tasks;
 using Desktop.Tasks.Extensions;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -21,6 +22,8 @@ protected override void OnStartup(StartupEventArgs e)
         var services = new ServiceCollection();
 
         services.AddSingleton<MainWindow>();
+        services.AddSingleton<TaskCreation>();
+        services.AddTransient<TaskCreationViewModel>();
         services.AddBackendTaskRepository(Config);
 
         var serviceProvider = services.BuildServiceProvider();

Desktop/MainWindow.xaml.cs

@@ -7,17 +7,21 @@ namespace Desktop;
 public partial class MainWindow : Window
 {
     private readonly ITaskRepository taskRepository;
+    private readonly TaskCreationViewModel taskCreationViewModel;
 
-    public MainWindow(ITaskRepository taskRepository)
+    public MainWindow(
+        ITaskRepository taskRepository,
+        TaskCreationViewModel taskCreationViewModel)
     {
         this.taskRepository = taskRepository;
+        this.taskCreationViewModel = taskCreationViewModel;
         InitializeComponent();
         NavigateToTaskList();
     }
 
     private void NavigateToTaskList()
     {
-        var tasksList = new TasksList(taskRepository);
+        var tasksList = new TasksList(taskRepository, taskCreationViewModel);
         Content.Content = tasksList;
     }
 

Desktop/Project/TasksList.xaml.cs

@@ -12,11 +12,15 @@ namespace Desktop.Project;
 public partial class TasksList : UserControl
 {
     private readonly ITaskRepository taskRepository;
+    private readonly TaskCreationViewModel taskCreationViewModel;
     private readonly ObservableCollection<Task> tasks = [];
 
-    public TasksList(ITaskRepository taskRepository)
+    public TasksList(
+        ITaskRepository taskRepository,
+        TaskCreationViewModel taskCreationViewModel)
     {
         this.taskRepository = taskRepository;
+        this.taskCreationViewModel = taskCreationViewModel;
 
         InitializeComponent();
         Tasks.ItemsSource = tasks;
@@ -29,14 +33,13 @@ public TasksList(ITaskRepository taskRepository)
 
     private void Add(object sender, RoutedEventArgs e)
     {
-        var window = new TaskCreation();
-        window.ShowDialog();
+        var taskCreationWindow = new TaskCreation(taskCreationViewModel);
+        taskCreationWindow.ShowDialog();
 
-        if (window.CreatedTask is null)
+        if (taskCreationWindow.CreatedTask is null)
             return;
 
-        tasks.Add(window.CreatedTask);
-        taskRepository.Save(window.CreatedTask);
+        tasks.Add(taskCreationWindow.CreatedTask);
     }
 
     private void Edit(object sender, MouseButtonEventArgs e)

Desktop/Tasks/Converters/SaveCommandConverter.cs

@@ -0,0 +1,26 @@
+using System.Globalization;
+using System.Windows.Data;
+using Desktop.Common;
+
+namespace Desktop.Tasks.Converters;
+
+public class SaveCommandConverter : IMultiValueConverter
+{
+    public object Convert(
+        object[] values,
+        Type targetType,
+        object parameter,
+        CultureInfo culture)
+    {
+        return (values[0] as ICloseable, values[1] as string, values[2] as string);
+    }
+
+    public object[] ConvertBack(
+        object value,
+        Type[] targetTypes,
+        object parameter,
+        CultureInfo culture)
+    {
+        throw new NotSupportedException();
+    }
+}

Desktop/Tasks/TaskCreation.xaml

@@ -3,14 +3,14 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-        xmlns:local="clr-namespace:Desktop.Tasks"
+        xmlns:converters="clr-namespace:Desktop.Tasks.Converters"
         mc:Ignorable="d"
         x:Name="TaskCreationWindow"
         Title="Task creation" Height="225" Width="400"
         WindowStartupLocation="CenterScreen">
-    <Window.DataContext>
-        <local:TaskCreationViewModel />
-    </Window.DataContext>
+    <Window.Resources>
+        <converters:SaveCommandConverter x:Key="SaveCommandConverter" />
+    </Window.Resources>
     <Grid FocusManager.FocusedElement="{Binding ElementName=Name}">
         <Grid.RowDefinitions>
             <RowDefinition Height="Auto" />
@@ -26,8 +26,14 @@
                  VerticalAlignment="Stretch" />
         <Button AutomationProperties.AutomationId="SaveTask" Grid.Row="4" Content="Add" HorizontalAlignment="Right"
                 IsDefault="True"
-                Click="SaveTask"
-                Command="{Binding SaveTask }"
-                CommandParameter="{Binding ElementName=TaskCreationWindow}" />
+                Command="{Binding SaveTask }">
+            <Button.CommandParameter>
+                <MultiBinding Converter="{StaticResource SaveCommandConverter}">
+                    <Binding ElementName="TaskCreationWindow" />
+                    <Binding ElementName="Name" Path="Text" />
+                    <Binding ElementName="Description" Path="Text" />
+                </MultiBinding>
+            </Button.CommandParameter>
+        </Button>
     </Grid>
 </Window>

Desktop/Tasks/TaskCreation.xaml.cs

@@ -8,15 +8,14 @@ namespace Desktop.Tasks;
 
 public partial class TaskCreation : Window, ICloseable
 {
-    public TaskCreation()
+    private readonly TaskCreationViewModel viewModel;
+
+    public TaskCreation(TaskCreationViewModel viewModel)
     {
         InitializeComponent();
+        DataContext = viewModel;
+        this.viewModel = viewModel;
     }
 
-    public Task? CreatedTask { get; private set; }
-
-    private void SaveTask(object sender, RoutedEventArgs e)
-    {
-        CreatedTask = new Task(name: Name.Text, description: Description.Text);
-    }
+    public Task? CreatedTask => viewModel.CreatedTask;
 }

Desktop/Tasks/TaskCreationViewModel.cs

@@ -1,11 +1,24 @@
-using System.Windows.Input;
-using CommunityToolkit.Mvvm.Input;
+using CommunityToolkit.Mvvm.Input;
 using Desktop.Common;
+using Task = Desktop.Domain.Task;
 
 namespace Desktop.Tasks;
 
 public class TaskCreationViewModel : ViewModelBase
 {
-    public ICommand SaveTask { get; } =
-        new RelayCommand<ICloseable>(closeable => { closeable.Close(); });
+    public TaskCreationViewModel(ITaskRepository taskRepository)
+    {
+        SaveTask =
+            new RelayCommand<(ICloseable, string, string)>((args) =>
+            {
+                var (closeable, taskName, taskDescription) = args;
+
+                CreatedTask = new Task(taskName, taskDescription);
+                taskRepository.Save(CreatedTask);
+                closeable!.Close();
+            });
+    }
+
+    public IRelayCommand SaveTask { get; }
+    public Task? CreatedTask { get; private set; }
 }