refactor: move request of showing the TaskCreationView to the TaskListViewModel thus completely removing the Add code behind

Author: Xiphereal

Desktop/Common/IShowable.cs

@@ -0,0 +1,6 @@
+namespace Desktop.Common;
+
+public interface IShowable
+{
+    bool? ShowDialog();
+}

Desktop/Project/TaskListViewModel.cs

@@ -13,13 +13,19 @@ public class TaskListViewModel : ViewModelBase
     private readonly ITaskRepository taskRepository;
     public ObservableCollection<Task> Tasks { get; } = [];
 
-    public TaskListViewModel(ITaskRepository taskRepository)
+    public Func<TaskCreationViewModel, IShowable> TaskCreationViewCreator { get; set; }
+
+    public TaskListViewModel(
+        ITaskRepository taskRepository,
+        TaskCreationViewModel taskCreationViewModel)
     {
         this.taskRepository = taskRepository;
 
-        Add = new RelayCommand<TaskCreationViewModel>(taskCreationViewModel =>
+        Add = new RelayCommand(() =>
         {
-            if (taskCreationViewModel!.CreatedTask is null)
+            TaskCreationViewCreator!(taskCreationViewModel).ShowDialog();
+
+            if (taskCreationViewModel.CreatedTask is null)
                 return;
 
             Tasks.Add(taskCreationViewModel.CreatedTask);

Desktop/Project/TasksList.xaml

@@ -14,7 +14,7 @@
         <StackPanel>
             <StackPanel Orientation="Horizontal">
                 <Label Content="Tasks:" />
-                <Button AutomationProperties.AutomationId="AddTask" Content="_Add task" Click="Add" />
+                <Button AutomationProperties.AutomationId="AddTask" Content="_Add task" Command="{Binding Add}" />
             </StackPanel>
 
             <ListBox Name="Tasks">

Desktop/Project/TasksList.xaml.cs

@@ -19,19 +19,15 @@ public TasksList(
     {
         this.taskRepository = taskRepository;
         this.viewModel = viewModel;
+        DataContext = viewModel;
         this.taskCreationViewModel = taskCreationViewModel;
 
         InitializeComponent();
         Tasks.ItemsSource = viewModel.Tasks;
 
         viewModel.PopulateTasks();
-    }
-
-    private void Add(object sender, RoutedEventArgs e)
-    {
-        new TaskCreation(taskCreationViewModel).ShowDialog();
-
-        viewModel.Add.Execute(taskCreationViewModel);
+        viewModel.TaskCreationViewCreator = creationViewModel =>
+            new TaskCreation(creationViewModel);
     }
 
     private void Edit(object sender, MouseButtonEventArgs e)

Desktop/Tasks/TaskCreation.xaml.cs

@@ -1,21 +1,13 @@
 using System.Windows;
 using Desktop.Common;
-using Task = Desktop.Domain.Task;
 
 namespace Desktop.Tasks;
 
-using Task = Task;
-
-public partial class TaskCreation : Window, ICloseable
+public partial class TaskCreation : Window, ICloseable, IShowable
 {
-    private readonly TaskCreationViewModel viewModel;
-
     public TaskCreation(TaskCreationViewModel viewModel)
     {
         InitializeComponent();
         DataContext = viewModel;
-        this.viewModel = viewModel;
     }
-
-    public Task? CreatedTask => viewModel.CreatedTask;
 }