Pre-select category when adding new snippet.

Improves the "Add Snippet" workflow by automatically selecting the
currently active category from the TreeView.

Author: mx7b7

src/CodeSnip/MainViewModel.cs

@@ -45,6 +45,9 @@ public partial class MainViewModel : ObservableObject
         [ObservableProperty]
         private Snippet? _selectedSnippet;
 
+        [ObservableProperty]
+        private Category? _selectedCategory;
+
         [ObservableProperty]
         private string _statusMessage = "Ready";
 
@@ -619,7 +622,7 @@ await DialogService.Instance.ShowMessageAsync("Cannot Add Snippet",
                 return;
             }
 
-            var vm = new SnippetViewModel(false, new Snippet(), [.. Languages], _databaseService);
+            var vm = new SnippetViewModel(false, new Snippet(), [.. Languages], _databaseService, SelectedCategory);
 
             _flyoutService.ShowFlyout("flySnippet", vm, " Add new snippet");
         }
@@ -953,6 +956,7 @@ public async Task ChangeSelectedSnippetAsync(Snippet? newSnippet)
 
             SelectedSnippet = newSnippet;
             EditingSnippet = newSnippet;
+            SelectedCategory = newSnippet.Category;
 
             _isInternalTextUpdate = true;
             EditorText = newSnippet.Code ?? string.Empty;

src/CodeSnip/MainWindow.xaml.cs

@@ -2,6 +2,7 @@
 using CodeSnip.Services;
 using CodeSnip.Services.Exporters;
 using CodeSnip.Views.HighlightingEditorView;
+using CodeSnip.Views.LanguageCategoryView;
 using CodeSnip.Views.SnippetView;
 using ControlzEx.Theming;
 using ICSharpCode.AvalonEdit;
@@ -257,6 +258,10 @@ private async void TreeView_SelectedItemChanged(object sender, RoutedPropertyCha
 
                 textEditor.Document.UndoStack.ClearAll();
             }
+            else if (e.NewValue is Category category)
+            {
+                mainViewModel.SelectedCategory = category;
+            }
         }
 
         private async void FormatDfmt_Click(object sender, RoutedEventArgs e)

src/CodeSnip/Views/SnippetView/SnippetView.xaml

@@ -49,15 +49,15 @@
         <Grid Grid.Row="1">
             <Grid.RowDefinitions>
                 <RowDefinition Height="Auto"/>
-                <!-- Red za Title -->
+                <!-- Title -->
                 <RowDefinition Height="Auto"/>
                 <!-- txtTitle -->
                 <RowDefinition Height="Auto"/>
-                <!-- Red za Description -->
+                <!-- Description -->
                 <RowDefinition Height="*"/>
                 <!-- txtDescription -->
                 <RowDefinition Height="Auto"/>
-                <!-- Red za Tag -->
+                <!-- Tag -->
                 <RowDefinition Height="Auto"/>
                 <!-- txtTag -->
             </Grid.RowDefinitions>
@@ -77,7 +77,7 @@
         </Grid>
         <!-- Blok 3 -->
         <StackPanel Grid.Row="2" Orientation="Horizontal" HorizontalAlignment="Right" Margin="0,20,0,0">
-            <Button x:Name="btnOk" Content="OK" Width="60" Command="{Binding SaveCommand}"/>
+            <Button x:Name="btnOk" Content="Save" Width="60" Command="{Binding SaveCommand}"  IsEnabled="{Binding SaveCommand.CanExecute}"/>
             <Button Content="Cancel" Margin="20,0,0,0" Width="60" Command="{Binding CancelCommand}"/>
         </StackPanel>
     </Grid>

src/CodeSnip/Views/SnippetView/SnippetViewModel.cs

@@ -15,9 +15,6 @@ public partial class SnippetViewModel : ObservableObject, IDataErrorInfo
         [ObservableProperty]
         private ObservableCollection<Language> _languages = [];
 
-        [ObservableProperty]
-        private ObservableCollection<Category> _categories = [];
-
         [ObservableProperty]
         private ObservableCollection<Category> _availableCategories = [];
 
@@ -36,6 +33,7 @@ public partial class SnippetViewModel : ObservableObject, IDataErrorInfo
         private string? _selectedLanguageName;
 
         [ObservableProperty]
+        [NotifyCanExecuteChangedFor(nameof(SaveCommand))]
         private string? _title = string.Empty;
 
         public string Error => "";
@@ -44,10 +42,9 @@ public string this[string _property]
         {
             get
             {
-                if (_property == nameof(Title))
+                if (_property == nameof(Title) && string.IsNullOrWhiteSpace(Title))
                 {
-                    if (string.IsNullOrWhiteSpace(Title))
-                        return "Title cannot be empty";
+                    return "Title cannot be empty";
                 }
                 return "";
             }
@@ -57,7 +54,8 @@ public SnippetViewModel(
             bool isEditMode,
             Snippet? snippet,
             List<Language>? languages,
-            DatabaseService? databaseService)
+            DatabaseService? databaseService,
+            Category? preselectedCategory = null)
         {
             ArgumentNullException.ThrowIfNull(databaseService);
 
@@ -67,12 +65,19 @@ public SnippetViewModel(
             Languages = new ObservableCollection<Language>(languages ?? new List<Language>());
             Snippet = snippet;
 
+            if (preselectedCategory != null)
+            {
+                SelectedCategory = preselectedCategory;
+            }
+
             InitializeSelections();
         }
 
         public bool CanSave()
         {
-            return string.IsNullOrWhiteSpace(this[nameof(Title)]);
+            // The command can be executed if there are no validation errors for the Title
+            // and a category is selected.
+            return string.IsNullOrEmpty(this[nameof(Title)]) && SelectedCategory != null;
         }
 
         private void InitializeSelections()
@@ -86,9 +91,17 @@ private void InitializeSelections()
             }
             else
             {
-                SelectedLanguage = Languages.FirstOrDefault();
-                AvailableCategories = new ObservableCollection<Category>(SelectedLanguage?.Categories ?? []);
-                SelectedCategory = AvailableCategories.FirstOrDefault();
+                if (SelectedCategory != null) // A category was pre-selected
+                {
+                    SelectedLanguage = SelectedCategory.Language;
+                    AvailableCategories = new ObservableCollection<Category>(SelectedLanguage?.Categories ?? []);
+                }
+                else // No pre-selection, start from scratch
+                {
+                    SelectedLanguage = Languages.FirstOrDefault();
+                    AvailableCategories = new ObservableCollection<Category>(SelectedLanguage?.Categories ?? []);
+                    SelectedCategory = AvailableCategories.FirstOrDefault();
+                }
             }
         }
 
@@ -97,7 +110,7 @@ partial void OnSelectedLanguageChanged(Language? value)
             AvailableCategories = new ObservableCollection<Category>(value?.Categories ?? new ObservableCollection<Category>());
             SelectedLanguageName = value?.Name;
 
-            if (!IsEditMode)
+            if (!IsEditMode && SelectedCategory == null)
                 SelectedCategory = AvailableCategories.FirstOrDefault();
         }
 
@@ -110,14 +123,11 @@ partial void OnSelectedCategoryChanged(Category? value)
             }
         }
 
-        [RelayCommand]
+        [RelayCommand(CanExecute = nameof(CanSave))]
         private void Save()
         {
             try
             {
-                if (!CanSave())
-                    return;
-
                 if (SelectedLanguage != null && SelectedCategory != null && Snippet != null)
                 {
                     Snippet.Title = Title ?? string.Empty;