feat: add tag manager, search filtering and export

YKanBan.Tests/Storage/Workspace/WorkspaceRepositoryTests.cs

@@ -1,5 +1,6 @@
 using Microsoft.Data.Sqlite;
 using YKanBan.Models;
+using YKanBan.Search;
 using YKanBan.Storage.Workspace;
 using YKanBan.Tests.TestUtilities;
 
@@ -257,6 +258,17 @@ public class WorkspaceRepositoryTests
             fixture.Repository.AddTag("bug", RgbColor.Parse("#123456"), ""));
     }
 
+    [TestMethod]
+    public void GetCardIdsMatchingRunsTheCompiledSearch()
+    {
+        using var fixture = new RepositoryFixture();
+        CompiledSearch compiled = SearchSqlCompiler.Compile(new SearchNode.FreeText("T"));
+
+        IReadOnlyCollection<long> ids = fixture.Repository.GetCardIdsMatching(compiled);
+
+        CollectionAssert.AreEquivalent(new[] { fixture.CardId }, ids.ToList());
+    }
+
     [TestMethod]
     public void GetTagsWithUsageCountsAssignments()
     {

YKanBan/App.axaml

@@ -12,6 +12,7 @@
     <Application.Styles>
         <!-- Semi.Avalonia provides the light and dark palettes; icons need their own theme. -->
         <semi:SemiTheme/>
+        <semi:ColorPickerSemiTheme/>
         <StyleInclude Source="avares://IconPacks.Avalonia.Lucide/Lucide.axaml"/>
     </Application.Styles>
 

YKanBan/Assets/Locales/Resources.resx

@@ -28,6 +28,9 @@
   <data name="Common_Delete" xml:space="preserve">
     <value>Delete</value>
   </data>
+  <data name="Common_Edit" xml:space="preserve">
+    <value>Edit</value>
+  </data>
   <data name="Main_Export" xml:space="preserve">
     <value>Export</value>
   </data>
@@ -70,6 +73,18 @@
   <data name="Board_NoColumns" xml:space="preserve">
     <value>No columns yet.</value>
   </data>
+  <data name="Board_FilterActive" xml:space="preserve">
+    <value>Board is filtered</value>
+  </data>
+  <data name="Board_FilterInactive" xml:space="preserve">
+    <value>Board is not filtered</value>
+  </data>
+  <data name="Search_Error_Title" xml:space="preserve">
+    <value>Invalid search</value>
+  </data>
+  <data name="Search_Error_Message" xml:space="preserve">
+    <value>The query expression is invalid. Details: {0}</value>
+  </data>
   <data name="Sort_IdAsc" xml:space="preserve">
     <value>ID Ascending</value>
   </data>
@@ -166,6 +181,39 @@
   <data name="TagDialog_NoTargets" xml:space="preserve">
     <value>There are no more tags to add.</value>
   </data>
+  <data name="Tags_AddTag" xml:space="preserve">
+    <value>Add Tag</value>
+  </data>
+  <data name="Tags_Empty" xml:space="preserve">
+    <value>No tags yet.</value>
+  </data>
+  <data name="Tags_Usage" xml:space="preserve">
+    <value>{0} cards</value>
+  </data>
+  <data name="TagEditor_AddTitle" xml:space="preserve">
+    <value>New Tag</value>
+  </data>
+  <data name="TagEditor_EditTitle" xml:space="preserve">
+    <value>Edit Tag</value>
+  </data>
+  <data name="TagEditor_Name" xml:space="preserve">
+    <value>Name</value>
+  </data>
+  <data name="TagEditor_Color" xml:space="preserve">
+    <value>Color</value>
+  </data>
+  <data name="TagEditor_Description" xml:space="preserve">
+    <value>Description</value>
+  </data>
+  <data name="TagEditor_InvalidName" xml:space="preserve">
+    <value>The name is empty or already used.</value>
+  </data>
+  <data name="DeleteTag_Confirm_Title" xml:space="preserve">
+    <value>Delete Tag</value>
+  </data>
+  <data name="DeleteTag_Confirm_Message" xml:space="preserve">
+    <value>Delete tag "{0}"? It will be removed from {1} card(s).</value>
+  </data>
   <data name="MoveDialog_Title" xml:space="preserve">
     <value>Move Card</value>
   </data>
@@ -391,4 +439,10 @@
   <data name="Export_TagsTableHeader" xml:space="preserve">
     <value>| Name | Color | Description | Usage |</value>
   </data>
+  <data name="Export_Done_Title" xml:space="preserve">
+    <value>Export Complete</value>
+  </data>
+  <data name="Export_Done_Message" xml:space="preserve">
+    <value>Exported to: {0}</value>
+  </data>
 </root>

YKanBan/Assets/Locales/Resources.zh-Hans.resx

@@ -28,6 +28,9 @@
   <data name="Common_Delete" xml:space="preserve">
     <value>删除</value>
   </data>
+  <data name="Common_Edit" xml:space="preserve">
+    <value>编辑</value>
+  </data>
   <data name="Main_Export" xml:space="preserve">
     <value>导出</value>
   </data>
@@ -70,6 +73,18 @@
   <data name="Board_NoColumns" xml:space="preserve">
     <value>还没有列。</value>
   </data>
+  <data name="Board_FilterActive" xml:space="preserve">
+    <value>看板处于过滤状态</value>
+  </data>
+  <data name="Board_FilterInactive" xml:space="preserve">
+    <value>看板未处于过滤状态</value>
+  </data>
+  <data name="Search_Error_Title" xml:space="preserve">
+    <value>搜索表达式有误</value>
+  </data>
+  <data name="Search_Error_Message" xml:space="preserve">
+    <value>查询表达式有误，详情：{0}</value>
+  </data>
   <data name="Sort_IdAsc" xml:space="preserve">
     <value>ID 正序</value>
   </data>
@@ -166,6 +181,39 @@
   <data name="TagDialog_NoTargets" xml:space="preserve">
     <value>没有可添加的标签。</value>
   </data>
+  <data name="Tags_AddTag" xml:space="preserve">
+    <value>添加标签</value>
+  </data>
+  <data name="Tags_Empty" xml:space="preserve">
+    <value>还没有标签。</value>
+  </data>
+  <data name="Tags_Usage" xml:space="preserve">
+    <value>{0} 张卡片</value>
+  </data>
+  <data name="TagEditor_AddTitle" xml:space="preserve">
+    <value>新建标签</value>
+  </data>
+  <data name="TagEditor_EditTitle" xml:space="preserve">
+    <value>编辑标签</value>
+  </data>
+  <data name="TagEditor_Name" xml:space="preserve">
+    <value>名称</value>
+  </data>
+  <data name="TagEditor_Color" xml:space="preserve">
+    <value>颜色</value>
+  </data>
+  <data name="TagEditor_Description" xml:space="preserve">
+    <value>描述</value>
+  </data>
+  <data name="TagEditor_InvalidName" xml:space="preserve">
+    <value>名称为空或已被使用。</value>
+  </data>
+  <data name="DeleteTag_Confirm_Title" xml:space="preserve">
+    <value>删除标签</value>
+  </data>
+  <data name="DeleteTag_Confirm_Message" xml:space="preserve">
+    <value>删除标签“{0}”？将从 {1} 张卡片中移除。</value>
+  </data>
   <data name="MoveDialog_Title" xml:space="preserve">
     <value>移动卡片</value>
   </data>
@@ -391,4 +439,10 @@
   <data name="Export_TagsTableHeader" xml:space="preserve">
     <value>| 名称 | 颜色 | 描述 | 使用数 |</value>
   </data>
+  <data name="Export_Done_Title" xml:space="preserve">
+    <value>导出完成</value>
+  </data>
+  <data name="Export_Done_Message" xml:space="preserve">
+    <value>已导出到：{0}</value>
+  </data>
 </root>

YKanBan/Storage/Workspace/WorkspaceRepository.cs

@@ -1,5 +1,6 @@
 using Microsoft.Data.Sqlite;
 using YKanBan.Models;
+using YKanBan.Search;
 
 namespace YKanBan.Storage.Workspace;
 
@@ -172,6 +173,28 @@ public sealed class WorkspaceRepository : IDisposable
         return cards;
     }
 
+    /// <summary>
+    /// Returns the ids of the cards matching a compiled search predicate.
+    /// </summary>
+    /// <param name="search">The compiled search predicate and its parameters.</param>
+    /// <returns>The matching card ids.</returns>
+    public IReadOnlyCollection<long> GetCardIdsMatching(CompiledSearch search)
+    {
+        using var command = CreateCommand($"SELECT c.id FROM cards c WHERE {search.Predicate};");
+        foreach ((string name, object value) in search.Parameters)
+        {
+            command.Parameters.AddWithValue(name, value);
+        }
+        using var reader = command.ExecuteReader();
+
+        var ids = new HashSet<long>();
+        while (reader.Read())
+        {
+            ids.Add(reader.GetInt64(0));
+        }
+        return ids;
+    }
+
     /// <summary>
     /// Returns the card with the given id, with its tags loaded.
     /// </summary>

YKanBan/ViewModels/Board/BoardViewModel.cs

@@ -2,6 +2,7 @@ using System.Collections.ObjectModel;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using YKanBan.Models;
+using YKanBan.Search;
 using YKanBan.Services;
 using YKanBan.Storage.AppData;
 using YKanBan.Storage.Workspace;
@@ -19,6 +20,9 @@ public sealed partial class BoardViewModel : ViewModelBase
     private readonly AppServices _services;
     private readonly WorkspaceRepository _repository;
 
+    // The active search result filter, or null when the whole board is shown.
+    private IReadOnlyCollection<long>? _matchedCardIds;
+
     /// <summary>
     /// Initializes the board, loading its current content.
     /// </summary>
@@ -66,6 +70,21 @@ public sealed partial class BoardViewModel : ViewModelBase
     [ObservableProperty]
     private double columnWidth;
 
+    /// <summary>
+    /// Gets a value indicating whether a search filter is currently applied.
+    /// </summary>
+    public bool IsFiltering => _matchedCardIds is not null;
+
+    /// <summary>
+    /// Gets the localized filter status text shown as the status icon tooltip.
+    /// </summary>
+    public string FilterStatusText => IsFiltering ? Resources.Board_FilterActive : Resources.Board_FilterInactive;
+
+    /// <summary>
+    /// Gets the status icon opacity: full while filtering, dimmed otherwise.
+    /// </summary>
+    public double FilterIconOpacity => IsFiltering ? 1.0 : 0.4;
+
     /// <summary>
     /// Gets a value indicating whether the board has any columns.
     /// </summary>
@@ -99,8 +118,8 @@ public sealed partial class BoardViewModel : ViewModelBase
     /// <summary>Gets the interaction that opens the move-card dialog.</summary>
     public Interaction<CardViewModel> MoveCard { get; } = new();
 
-    /// <summary>Gets the interaction that runs the current search.</summary>
-    public Interaction<Unit> RunSearch { get; } = new();
+    /// <summary>Gets the interaction that shows the search error dialog, carrying the English parser detail.</summary>
+    public Interaction<string> ShowSearchError { get; } = new();
 
     #endregion
 
@@ -113,16 +132,64 @@ public sealed partial class BoardViewModel : ViewModelBase
     private Task AddNewColumnAsync() => AddColumn.Handle(Unit.Value);
 
     /// <summary>
-    /// Runs the current search (wired up with the search feature).
+    /// Runs the current search. A blank query shows everything; an invalid
+    /// expression opens the error dialog and keeps the previous results and text.
     /// </summary>
     [RelayCommand]
-    private Task SearchAsync() => RunSearch.Handle(Unit.Value);
+    private async Task SearchAsync()
+    {
+        if (string.IsNullOrWhiteSpace(SearchText))
+        {
+            ApplyFilter(null);
+            return;
+        }
+
+        try
+        {
+            SearchNode? query = SearchQueryParser.Parse(SearchText);
+            if (query is null)
+            {
+                ApplyFilter(null);
+                return;
+            }
+
+            CompiledSearch compiled = SearchSqlCompiler.Compile(query);
+            ApplyFilter(_repository.GetCardIdsMatching(compiled));
+        }
+        catch (SearchSyntaxException exception)
+        {
+            // The error dialog carries the parser's non-localized English detail.
+            await ShowSearchError.Handle(exception.Message);
+        }
+    }
 
     /// <summary>
-    /// Clears the search box.
+    /// Clears the search box and restores the unfiltered board.
     /// </summary>
     [RelayCommand]
-    private void ClearSearch() => SearchText = string.Empty;
+    private void ClearSearch()
+    {
+        SearchText = string.Empty;
+        ApplyFilter(null);
+    }
+
+    /// <summary>
+    /// Applies a new result filter (null clears it) and rebuilds the board when it changed.
+    /// </summary>
+    /// <param name="matchedIds">The new filter, or <see langword="null"/> for no filter.</param>
+    private void ApplyFilter(IReadOnlyCollection<long>? matchedIds)
+    {
+        if (_matchedCardIds is null && matchedIds is null)
+        {
+            return;
+        }
+
+        _matchedCardIds = matchedIds;
+        OnPropertyChanged(nameof(IsFiltering));
+        OnPropertyChanged(nameof(FilterStatusText));
+        OnPropertyChanged(nameof(FilterIconOpacity));
+        Reload();
+    }
 
     #endregion
 
@@ -182,6 +249,12 @@ public sealed partial class BoardViewModel : ViewModelBase
         IReadOnlyList<ColumnModel> columns = _repository.GetColumns();
         IReadOnlyList<CardModel> cards = _repository.GetCards();
 
+        // An active search hides non-matching cards while every column stays visible.
+        if (_matchedCardIds is not null)
+        {
+            cards = cards.Where(card => _matchedCardIds.Contains(card.Id)).ToList();
+        }
+
         // Group cards by column once so each column can be built independently.
         Dictionary<long, List<CardModel>> cardsByColumn = cards
             .GroupBy(card => card.ColumnId)

YKanBan/ViewModels/Dialogs/DeleteTagConfirmViewModel.cs

@@ -0,0 +1,29 @@
+using System.Globalization;
+
+namespace YKanBan.ViewModels.Dialogs;
+
+/// <summary>
+/// The confirmation shown before deleting a tag, naming the tag and how many
+/// cards it will be removed from.
+/// </summary>
+public sealed class DeleteTagConfirmViewModel : ViewModelBase
+{
+    /// <summary>
+    /// Initializes the confirmation.
+    /// </summary>
+    /// <param name="tagName">The name of the tag to delete.</param>
+    /// <param name="usageCount">The number of cards using the tag.</param>
+    public DeleteTagConfirmViewModel(string tagName, long usageCount)
+    {
+        Message = string.Format(
+            Resources.Culture ?? CultureInfo.CurrentCulture,
+            Resources.DeleteTag_Confirm_Message,
+            tagName,
+            usageCount);
+    }
+
+    /// <summary>
+    /// Gets the localized confirmation message.
+    /// </summary>
+    public string Message { get; }
+}

YKanBan/ViewModels/Dialogs/ExportDoneViewModel.cs

@@ -0,0 +1,25 @@
+using System.Globalization;
+
+namespace YKanBan.ViewModels.Dialogs;
+
+/// <summary>
+/// The confirmation dialog shown after a successful Markdown export, naming the
+/// written file.
+/// </summary>
+public sealed class ExportDoneViewModel : ViewModelBase
+{
+    /// <summary>
+    /// Initializes the dialog with the exported file path.
+    /// </summary>
+    /// <param name="filePath">The path the export was written to.</param>
+    public ExportDoneViewModel(string filePath)
+    {
+        Message = string.Format(
+            Resources.Culture ?? CultureInfo.CurrentCulture, Resources.Export_Done_Message, filePath);
+    }
+
+    /// <summary>
+    /// Gets the localized confirmation message.
+    /// </summary>
+    public string Message { get; }
+}

YKanBan/ViewModels/Dialogs/SearchErrorViewModel.cs

@@ -0,0 +1,27 @@
+using System.Globalization;
+
+namespace YKanBan.ViewModels.Dialogs;
+
+/// <summary>
+/// The pure-information dialog shown when the search expression is invalid. It
+/// wraps the parser's non-localized English detail in the localized message.
+/// </summary>
+public sealed class SearchErrorViewModel : ViewModelBase
+{
+    /// <summary>
+    /// Initializes the dialog with the parser's English detail.
+    /// </summary>
+    /// <param name="detail">The non-localized parser error description.</param>
+    public SearchErrorViewModel(string detail)
+    {
+        Message = string.Format(
+            Resources.Culture ?? CultureInfo.CurrentCulture,
+            Resources.Search_Error_Message,
+            detail);
+    }
+
+    /// <summary>
+    /// Gets the localized error message.
+    /// </summary>
+    public string Message { get; }
+}

YKanBan/ViewModels/Dialogs/TagEditorViewModel.cs

@@ -0,0 +1,97 @@
+using Avalonia.Media;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Microsoft.Data.Sqlite;
+using YKanBan.Models;
+using YKanBan.Storage.Workspace;
+
+namespace YKanBan.ViewModels.Dialogs;
+
+/// <summary>
+/// The add/edit tag dialog: a name, a color chosen with a color picker and an
+/// optional description. The write happens when the dialog is accepted; a
+/// duplicate or empty name keeps the dialog open with an inline error.
+/// </summary>
+public sealed partial class TagEditorViewModel : ViewModelBase
+{
+    private readonly WorkspaceRepository _repository;
+    private readonly TagModel? _existing;
+
+    /// <summary>
+    /// Initializes the dialog for a new or existing tag.
+    /// </summary>
+    /// <param name="repository">The workspace repository.</param>
+    /// <param name="existing">The tag to edit, or <see langword="null"/> to add one.</param>
+    public TagEditorViewModel(WorkspaceRepository repository, TagModel? existing)
+    {
+        _repository = repository;
+        _existing = existing;
+        name = existing?.Name ?? string.Empty;
+        description = existing?.Description ?? string.Empty;
+        color = existing is not null
+            ? Color.FromRgb(existing.Color.R, existing.Color.G, existing.Color.B)
+            : Colors.Gray;
+    }
+
+    /// <summary>
+    /// Gets a value indicating whether this dialog creates a new tag.
+    /// </summary>
+    public bool IsNew => _existing is null;
+
+    /// <summary>
+    /// Gets the localized window title.
+    /// </summary>
+    public string WindowTitle => IsNew ? Resources.TagEditor_AddTitle : Resources.TagEditor_EditTitle;
+
+    /// <summary>
+    /// Gets or sets the tag name.
+    /// </summary>
+    [ObservableProperty]
+    private string name;
+
+    /// <summary>
+    /// Gets or sets the tag color.
+    /// </summary>
+    [ObservableProperty]
+    private Color color;
+
+    /// <summary>
+    /// Gets or sets the tag description.
+    /// </summary>
+    [ObservableProperty]
+    private string description;
+
+    /// <summary>
+    /// Gets or sets the inline error shown when the name is rejected.
+    /// </summary>
+    [ObservableProperty]
+    private string? errorMessage;
+
+    /// <summary>
+    /// Writes the tag when accepted.
+    /// </summary>
+    /// <returns><see langword="true"/> when the dialog may close.</returns>
+    public bool TryAccept()
+    {
+        ErrorMessage = null;
+        var rgb = new RgbColor(Color.R, Color.G, Color.B);
+
+        try
+        {
+            if (_existing is null)
+            {
+                _repository.AddTag(Name, rgb, Description);
+            }
+            else
+            {
+                _repository.UpdateTag(_existing.Id, Name, rgb, Description);
+            }
+
+            return true;
+        }
+        catch (SqliteException)
+        {
+            ErrorMessage = Resources.TagEditor_InvalidName;
+            return false;
+        }
+    }
+}

YKanBan/ViewModels/Tags/TagItemViewModel.cs

@@ -0,0 +1,78 @@
+using System.Globalization;
+using CommunityToolkit.Mvvm.Input;
+using YKanBan.Models;
+using YKanBan.ViewModels.Board;
+
+namespace YKanBan.ViewModels.Tags;
+
+/// <summary>
+/// One row of the tag manager: a color swatch, the name, the description and the
+/// usage count, plus edit and delete actions.
+/// </summary>
+public sealed partial class TagItemViewModel
+{
+    private readonly TagsViewModel _owner;
+
+    /// <summary>
+    /// Initializes the row.
+    /// </summary>
+    /// <param name="owner">The owning tag manager.</param>
+    /// <param name="tag">The tag model.</param>
+    /// <param name="usageCount">The number of cards using the tag.</param>
+    public TagItemViewModel(TagsViewModel owner, TagModel tag, long usageCount)
+    {
+        _owner = owner;
+        Tag = tag;
+        Badge = new TagBadgeViewModel(tag);
+        UsageCount = usageCount;
+        UsageText = string.Format(
+            Resources.Culture ?? CultureInfo.CurrentCulture, Resources.Tags_Usage, usageCount);
+    }
+
+    /// <summary>
+    /// Gets the underlying tag model.
+    /// </summary>
+    public TagModel Tag { get; }
+
+    /// <summary>
+    /// Gets the colored badge for the swatch and name.
+    /// </summary>
+    public TagBadgeViewModel Badge { get; }
+
+    /// <summary>
+    /// Gets the tag name.
+    /// </summary>
+    public string Name => Tag.Name;
+
+    /// <summary>
+    /// Gets the tag description.
+    /// </summary>
+    public string Description => Tag.Description;
+
+    /// <summary>
+    /// Gets a value indicating whether the tag has a description.
+    /// </summary>
+    public bool HasDescription => Tag.Description.Length > 0;
+
+    /// <summary>
+    /// Gets the number of cards using the tag.
+    /// </summary>
+    public long UsageCount { get; }
+
+    /// <summary>
+    /// Gets the localized usage count.
+    /// </summary>
+    public string UsageText { get; }
+
+    /// <summary>
+    /// Asks the manager to edit this tag.
+    /// </summary>
+    [RelayCommand]
+    private void Edit() => _ = _owner.RequestEditAsync(this);
+
+    /// <summary>
+    /// Asks the manager to delete this tag.
+    /// </summary>
+    [RelayCommand]
+    private void Delete() => _ = _owner.RequestDeleteAsync(this);
+}

YKanBan/ViewModels/Tags/TagsViewModel.cs

@@ -0,0 +1,102 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.Input;
+using YKanBan.Models;
+using YKanBan.Storage.Workspace;
+
+namespace YKanBan.ViewModels.Tags;
+
+/// <summary>
+/// The tags tab: a manager for the workspace's tags (create, rename, recolor,
+/// re-describe and delete), showing each tag's color, name, description and
+/// usage count. Tag changes also refresh the board.
+/// </summary>
+public sealed partial class TagsViewModel : ViewModelBase
+{
+    private readonly WorkspaceRepository _repository;
+    private readonly Action _boardChanged;
+
+    /// <summary>
+    /// Initializes the manager, loading the current tags.
+    /// </summary>
+    /// <param name="repository">The workspace repository.</param>
+    /// <param name="boardChanged">Invoked after a tag change so the board refreshes.</param>
+    public TagsViewModel(WorkspaceRepository repository, Action boardChanged)
+    {
+        _repository = repository;
+        _boardChanged = boardChanged;
+        Reload();
+    }
+
+    /// <summary>
+    /// Gets the workspace repository used for tag access.
+    /// </summary>
+    public WorkspaceRepository Repository => _repository;
+
+    /// <summary>
+    /// Gets the tags in id order.
+    /// </summary>
+    public ObservableCollection<TagItemViewModel> Tags { get; } = [];
+
+    /// <summary>
+    /// Gets a value indicating whether the workspace has any tags.
+    /// </summary>
+    public bool HasTags => Tags.Count > 0;
+
+    /// <summary>
+    /// Gets a value indicating whether the workspace has no tags.
+    /// </summary>
+    public bool HasNoTags => Tags.Count == 0;
+
+    /// <summary>Gets the interaction that opens the new-tag editor.</summary>
+    public Interaction<Unit> AddTag { get; } = new();
+
+    /// <summary>Gets the interaction that opens the tag editor.</summary>
+    public Interaction<TagItemViewModel> EditTag { get; } = new();
+
+    /// <summary>Gets the interaction that confirms and deletes a tag.</summary>
+    public Interaction<TagItemViewModel> DeleteTag { get; } = new();
+
+    /// <summary>
+    /// Opens the new-tag editor.
+    /// </summary>
+    [RelayCommand]
+    private Task AddNewTagAsync() => AddTag.Handle(Unit.Value);
+
+    /// <summary>
+    /// Requests the editor for a tag.
+    /// </summary>
+    /// <param name="item">The tag to edit.</param>
+    /// <returns>A task completing after the editor closes.</returns>
+    public Task RequestEditAsync(TagItemViewModel item) => EditTag.Handle(item);
+
+    /// <summary>
+    /// Requests deletion of a tag.
+    /// </summary>
+    /// <param name="item">The tag to delete.</param>
+    /// <returns>A task completing after confirmation.</returns>
+    public Task RequestDeleteAsync(TagItemViewModel item) => DeleteTag.Handle(item);
+
+    /// <summary>
+    /// Reloads the tag list from the repository.
+    /// </summary>
+    public void Reload()
+    {
+        Tags.Clear();
+        foreach ((TagModel tag, long usage) in _repository.GetTagsWithUsage())
+        {
+            Tags.Add(new TagItemViewModel(this, tag, usage));
+        }
+
+        OnPropertyChanged(nameof(HasTags));
+        OnPropertyChanged(nameof(HasNoTags));
+    }
+
+    /// <summary>
+    /// Reloads the tags and refreshes the board after a tag change.
+    /// </summary>
+    public void RefreshAfterChange()
+    {
+        Reload();
+        _boardChanged();
+    }
+}

YKanBan/ViewModels/WorkspaceViewModel.cs

@@ -2,6 +2,7 @@ using CommunityToolkit.Mvvm.Input;
 using YKanBan.Services;
 using YKanBan.Storage.Workspace;
 using YKanBan.ViewModels.Board;
+using YKanBan.ViewModels.Tags;
 
 namespace YKanBan.ViewModels;
 
@@ -32,7 +33,10 @@ public sealed partial class WorkspaceViewModel : ViewModelBase
         WorkspacePath = session.FolderPath;
         _showSettings = showSettings;
         _showAbout = showAbout;
+
+        // Both tabs share the same repository; tag changes refresh the board.
         Board = new BoardViewModel(services, session);
+        Tags = new TagsViewModel(session.Repository, Board.Reload);
     }
 
     /// <summary>
@@ -55,6 +59,16 @@ public sealed partial class WorkspaceViewModel : ViewModelBase
     /// </summary>
     public BoardViewModel Board { get; }
 
+    /// <summary>
+    /// Gets the tags tab view model.
+    /// </summary>
+    public TagsViewModel Tags { get; }
+
+    /// <summary>
+    /// Gets the interaction that runs the export flow.
+    /// </summary>
+    public Interaction<Unit> Export { get; } = new();
+
     /// <summary>
     /// Opens the settings dialog through the registered interaction.
     /// </summary>
@@ -68,11 +82,8 @@ public sealed partial class WorkspaceViewModel : ViewModelBase
     private async Task OpenAboutAsync() => await _showAbout.Handle(Unit.Value);
 
     /// <summary>
-    /// Raised by the export button; the export flow is wired up with the export
-    /// feature.
+    /// Runs the export flow through the registered interaction.
     /// </summary>
     [RelayCommand]
-    private static void Export()
-    {
-    }
+    private async Task RunExportAsync() => await Export.Handle(Unit.Value);
 }

YKanBan/Views/Board/BoardView.axaml

@@ -13,28 +13,40 @@
     <Grid RowDefinitions="Auto,*">
 
         <!-- Toolbar: search, add column and the combined display options. -->
-        <Grid Grid.Row="0" Margin="8" ColumnDefinitions="*,Auto,Auto,Auto,Auto">
-            <TextBox Grid.Column="0" Text="{Binding SearchText}" VerticalAlignment="Center"
-                     Watermark="{x:Static lang:Resources.Board_SearchPlaceholder}"/>
+        <Grid Grid.Row="0" Margin="8" ColumnDefinitions="Auto,*,Auto,Auto,Auto,Auto">
+            <!-- Wrapped in a transparent-border hit area so the tooltip triggers across the whole 16x16 box. -->
+            <Border Grid.Column="0" Background="Transparent" Padding="2" Margin="0,0,6,0"
+                    VerticalAlignment="Center"
+                    ToolTip.Tip="{Binding FilterStatusText}">
+                <icons:PackIconLucide Kind="ListFilter" Width="16" Height="16"
+                                      Opacity="{Binding FilterIconOpacity}"/>
+            </Border>
 
-            <Button Grid.Column="1" Margin="4,0,0,0" Command="{Binding ClearSearchCommand}"
+            <TextBox Grid.Column="1" Text="{Binding SearchText}" VerticalAlignment="Center"
+                     Watermark="{x:Static lang:Resources.Board_SearchPlaceholder}">
+                <TextBox.KeyBindings>
+                    <KeyBinding Gesture="Enter" Command="{Binding SearchCommand}"/>
+                </TextBox.KeyBindings>
+            </TextBox>
+
+            <Button Grid.Column="2" Margin="4,0,0,0" Command="{Binding ClearSearchCommand}"
                     ToolTip.Tip="{x:Static lang:Resources.Board_ClearSearch}">
                 <icons:PackIconLucide Kind="X" Width="16" Height="16"/>
             </Button>
 
-            <Button Grid.Column="2" Margin="4,0,0,0" Command="{Binding SearchCommand}"
+            <Button Grid.Column="3" Margin="4,0,0,0" Command="{Binding SearchCommand}"
                     ToolTip.Tip="{x:Static lang:Resources.Board_Search}">
                 <icons:PackIconLucide Kind="Search" Width="16" Height="16"/>
             </Button>
 
-            <Button Grid.Column="3" Margin="12,0,0,0" Command="{Binding AddNewColumnCommand}">
+            <Button Grid.Column="4" Margin="12,0,0,0" Command="{Binding AddNewColumnCommand}">
                 <StackPanel Orientation="Horizontal" Spacing="6">
                     <icons:PackIconLucide Kind="Plus" Width="16" Height="16"/>
                     <TextBlock Text="{x:Static lang:Resources.Board_AddColumn}"/>
                 </StackPanel>
             </Button>
 
-            <Button Grid.Column="4" Margin="4,0,0,0">
+            <Button Grid.Column="5" Margin="4,0,0,0">
                 <StackPanel Orientation="Horizontal" Spacing="6">
                     <icons:PackIconLucide Kind="SlidersHorizontal" Width="16" Height="16"/>
                     <TextBlock Text="{x:Static lang:Resources.Board_Display}"/>

YKanBan/Views/Board/BoardView.axaml.cs

@@ -27,9 +27,7 @@ public partial class BoardView : UserControl
             board.EditCard.RegisterHandler(card => EditCardAsync(board, null, card));
             board.DeleteCard.RegisterHandler(card => DeleteCardAsync(board, card));
             board.MoveCard.RegisterHandler(card => MoveCardAsync(board, card));
-
-            // The search button is present in the shell; searching arrives with the search feature.
-            board.RunSearch.RegisterHandler(_ => Task.CompletedTask);
+            board.ShowSearchError.RegisterHandler(ShowSearchErrorAsync);
         }
     }
 
@@ -145,4 +143,19 @@ public partial class BoardView : UserControl
             board.Reload();
         }
     }
+
+    /// <summary>Shows the search syntax error dialog.</summary>
+    private async Task ShowSearchErrorAsync(string detail)
+    {
+        if (OwningWindow is not Window owner)
+        {
+            return;
+        }
+
+        var dialog = new SearchErrorDialog
+        {
+            DataContext = new SearchErrorViewModel(detail),
+        };
+        await dialog.ShowDialog(owner);
+    }
 }

YKanBan/Views/Dialogs/DeleteTagConfirmDialog.axaml

@@ -0,0 +1,24 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="using:YKanBan.ViewModels.Dialogs"
+        xmlns:lang="using:YKanBan"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d" d:DesignWidth="420" d:DesignHeight="200"
+        x:Class="YKanBan.Views.Dialogs.DeleteTagConfirmDialog"
+        x:DataType="vm:DeleteTagConfirmViewModel"
+        Title="{x:Static lang:Resources.DeleteTag_Confirm_Title}"
+        Width="420" Height="200" MinWidth="420" MinHeight="200" CanResize="True"
+        WindowStartupLocation="CenterOwner"
+        ShowInTaskbar="False">
+
+    <Grid RowDefinitions="*,Auto" Margin="20">
+        <TextBlock Grid.Row="0" Text="{Binding Message}" TextWrapping="Wrap" VerticalAlignment="Top"/>
+        <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Right" Spacing="8">
+            <Button Content="{x:Static lang:Resources.Common_Delete}" Click="OnConfirmClick"
+                    MinWidth="90" IsDefault="True"/>
+            <Button Content="{x:Static lang:Resources.Common_Cancel}" Click="OnCancelClick"
+                    MinWidth="90" IsCancel="True"/>
+        </StackPanel>
+    </Grid>
+</Window>

YKanBan/Views/Dialogs/DeleteTagConfirmDialog.axaml.cs

@@ -0,0 +1,18 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+
+namespace YKanBan.Views.Dialogs;
+
+public partial class DeleteTagConfirmDialog : Window
+{
+    public DeleteTagConfirmDialog()
+    {
+        InitializeComponent();
+    }
+
+    /// <summary>Confirms the deletion.</summary>
+    private void OnConfirmClick(object? sender, RoutedEventArgs e) => Close(true);
+
+    /// <summary>Cancels the deletion.</summary>
+    private void OnCancelClick(object? sender, RoutedEventArgs e) => Close(false);
+}

YKanBan/Views/Dialogs/ExportDoneDialog.axaml

@@ -0,0 +1,21 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="using:YKanBan.ViewModels.Dialogs"
+        xmlns:lang="using:YKanBan"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d" d:DesignWidth="460" d:DesignHeight="200"
+        x:Class="YKanBan.Views.Dialogs.ExportDoneDialog"
+        x:DataType="vm:ExportDoneViewModel"
+        Title="{x:Static lang:Resources.Export_Done_Title}"
+        Width="460" Height="200" MinWidth="460" MinHeight="200" CanResize="True"
+        WindowStartupLocation="CenterOwner"
+        ShowInTaskbar="False">
+
+    <Grid RowDefinitions="*,Auto" Margin="20">
+        <TextBlock Grid.Row="0" Text="{Binding Message}" TextWrapping="Wrap" VerticalAlignment="Top"/>
+        <Button Grid.Row="1" Content="{x:Static lang:Resources.Common_Ok}"
+                Click="OnOkClick" HorizontalAlignment="Right" MinWidth="90"
+                IsDefault="True" IsCancel="True"/>
+    </Grid>
+</Window>

YKanBan/Views/Dialogs/ExportDoneDialog.axaml.cs

@@ -0,0 +1,15 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+
+namespace YKanBan.Views.Dialogs;
+
+public partial class ExportDoneDialog : Window
+{
+    public ExportDoneDialog()
+    {
+        InitializeComponent();
+    }
+
+    /// <summary>Closes the dialog.</summary>
+    private void OnOkClick(object? sender, RoutedEventArgs e) => Close();
+}

YKanBan/Views/Dialogs/SearchErrorDialog.axaml

@@ -0,0 +1,21 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="using:YKanBan.ViewModels.Dialogs"
+        xmlns:lang="using:YKanBan"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d" d:DesignWidth="440" d:DesignHeight="200"
+        x:Class="YKanBan.Views.Dialogs.SearchErrorDialog"
+        x:DataType="vm:SearchErrorViewModel"
+        Title="{x:Static lang:Resources.Search_Error_Title}"
+        Width="440" Height="200" MinWidth="440" MinHeight="200" CanResize="True"
+        WindowStartupLocation="CenterOwner"
+        ShowInTaskbar="False">
+
+    <Grid RowDefinitions="*,Auto" Margin="20">
+        <TextBlock Grid.Row="0" Text="{Binding Message}" TextWrapping="Wrap" VerticalAlignment="Top"/>
+        <Button Grid.Row="1" Content="{x:Static lang:Resources.Common_Ok}"
+                Click="OnOkClick" HorizontalAlignment="Right" MinWidth="90"
+                IsDefault="True" IsCancel="True"/>
+    </Grid>
+</Window>

YKanBan/Views/Dialogs/SearchErrorDialog.axaml.cs

@@ -0,0 +1,15 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+
+namespace YKanBan.Views.Dialogs;
+
+public partial class SearchErrorDialog : Window
+{
+    public SearchErrorDialog()
+    {
+        InitializeComponent();
+    }
+
+    /// <summary>Closes the dialog.</summary>
+    private void OnOkClick(object? sender, RoutedEventArgs e) => Close();
+}

YKanBan/Views/Dialogs/TagEditorDialog.axaml

@@ -0,0 +1,39 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="using:YKanBan.ViewModels.Dialogs"
+        xmlns:lang="using:YKanBan"
+        xmlns:conv="using:Avalonia.Data.Converters"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d" d:DesignWidth="440" d:DesignHeight="380"
+        x:Class="YKanBan.Views.Dialogs.TagEditorDialog"
+        x:DataType="vm:TagEditorViewModel"
+        Title="{Binding WindowTitle}"
+        Width="440" Height="380" MinWidth="440" MinHeight="380" CanResize="True"
+        WindowStartupLocation="CenterOwner"
+        ShowInTaskbar="False">
+
+    <Grid RowDefinitions="*,Auto" Margin="20">
+        <StackPanel Grid.Row="0" Spacing="6">
+            <TextBlock Text="{x:Static lang:Resources.TagEditor_Name}"/>
+            <TextBox Text="{Binding Name}"/>
+
+            <TextBlock Text="{x:Static lang:Resources.TagEditor_Color}" Margin="0,6,0,0"/>
+            <ColorPicker Color="{Binding Color, Mode=TwoWay}" HorizontalAlignment="Left"/>
+
+            <TextBlock Text="{x:Static lang:Resources.TagEditor_Description}" Margin="0,6,0,0"/>
+            <TextBox Text="{Binding Description}" AcceptsReturn="True" TextWrapping="Wrap"
+                     VerticalContentAlignment="Top" Height="70"/>
+
+            <TextBlock Text="{Binding ErrorMessage}"
+                       IsVisible="{Binding ErrorMessage, Converter={x:Static conv:ObjectConverters.IsNotNull}}"
+                       Foreground="{DynamicResource ErrorTextBrush}" TextWrapping="Wrap" Margin="0,4,0,0"/>
+        </StackPanel>
+
+        <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Right"
+                    Spacing="8" Margin="0,16,0,0">
+            <Button Content="{x:Static lang:Resources.Common_Ok}" Click="OnOkClick" MinWidth="90" IsDefault="True"/>
+            <Button Content="{x:Static lang:Resources.Common_Cancel}" Click="OnCancelClick" MinWidth="90" IsCancel="True"/>
+        </StackPanel>
+    </Grid>
+</Window>

YKanBan/Views/Dialogs/TagEditorDialog.axaml.cs

@@ -0,0 +1,25 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using YKanBan.ViewModels.Dialogs;
+
+namespace YKanBan.Views.Dialogs;
+
+public partial class TagEditorDialog : Window
+{
+    public TagEditorDialog()
+    {
+        InitializeComponent();
+    }
+
+    /// <summary>Writes the tag and closes when accepted.</summary>
+    private void OnOkClick(object? sender, RoutedEventArgs e)
+    {
+        if (DataContext is TagEditorViewModel viewModel && viewModel.TryAccept())
+        {
+            Close(true);
+        }
+    }
+
+    /// <summary>Closes without writing.</summary>
+    private void OnCancelClick(object? sender, RoutedEventArgs e) => Close(false);
+}

YKanBan/Views/Tags/TagsView.axaml

@@ -0,0 +1,62 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:vm="using:YKanBan.ViewModels.Tags"
+             xmlns:lang="using:YKanBan"
+             xmlns:icons="using:IconPacks.Avalonia.Lucide"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             mc:Ignorable="d" d:DesignWidth="1000" d:DesignHeight="600"
+             x:Class="YKanBan.Views.Tags.TagsView"
+             x:DataType="vm:TagsViewModel">
+
+    <Grid RowDefinitions="Auto,*" Margin="8">
+
+        <Button Grid.Row="0" Command="{Binding AddNewTagCommand}"
+                HorizontalAlignment="Right" Margin="0,0,0,8">
+            <StackPanel Orientation="Horizontal" Spacing="6">
+                <icons:PackIconLucide Kind="Plus" Width="16" Height="16"/>
+                <TextBlock Text="{x:Static lang:Resources.Tags_AddTag}"/>
+            </StackPanel>
+        </Button>
+
+        <ScrollViewer Grid.Row="1" VerticalScrollBarVisibility="Auto">
+            <ItemsControl ItemsSource="{Binding Tags}">
+                <ItemsControl.ItemTemplate>
+                    <DataTemplate x:DataType="vm:TagItemViewModel">
+                        <Border BorderBrush="{DynamicResource CardBorderBrush}"
+                                BorderThickness="0,0,0,1" Padding="8">
+                            <Grid ColumnDefinitions="Auto,*,Auto,Auto">
+                                <Border Grid.Column="0" Width="16" Height="16" CornerRadius="4"
+                                        Background="{Binding Badge.Background}"
+                                        VerticalAlignment="Center" Margin="0,0,10,0"/>
+
+                                <StackPanel Grid.Column="1" Spacing="2">
+                                    <TextBlock Text="{Binding Name}" FontWeight="SemiBold"/>
+                                    <TextBlock Text="{Binding Description}" IsVisible="{Binding HasDescription}"
+                                               Opacity="0.7" FontSize="12" TextWrapping="Wrap"/>
+                                    <TextBlock Text="{Binding UsageText}" Opacity="0.6" FontSize="12"/>
+                                </StackPanel>
+
+                                <Button Grid.Column="2" Command="{Binding EditCommand}" Padding="4,2" Margin="4,0"
+                                        VerticalAlignment="Center"
+                                        ToolTip.Tip="{x:Static lang:Resources.Common_Edit}">
+                                    <icons:PackIconLucide Kind="Pencil" Width="16" Height="16"/>
+                                </Button>
+                                <Button Grid.Column="3" Command="{Binding DeleteCommand}" Padding="4,2"
+                                        VerticalAlignment="Center"
+                                        ToolTip.Tip="{x:Static lang:Resources.Common_Delete}">
+                                    <icons:PackIconLucide Kind="Trash2" Width="16" Height="16"/>
+                                </Button>
+                            </Grid>
+                        </Border>
+                    </DataTemplate>
+                </ItemsControl.ItemTemplate>
+            </ItemsControl>
+        </ScrollViewer>
+
+        <TextBlock Grid.Row="1" Text="{x:Static lang:Resources.Tags_Empty}"
+                   IsVisible="{Binding HasNoTags}"
+                   HorizontalAlignment="Center" VerticalAlignment="Center" Opacity="0.6"/>
+
+    </Grid>
+</UserControl>

YKanBan/Views/Tags/TagsView.axaml.cs

@@ -0,0 +1,76 @@
+using Avalonia.Controls;
+using YKanBan.ViewModels.Dialogs;
+using YKanBan.ViewModels.Tags;
+using YKanBan.Views.Dialogs;
+
+namespace YKanBan.Views.Tags;
+
+public partial class TagsView : UserControl
+{
+    private bool _registered;
+
+    public TagsView()
+    {
+        InitializeComponent();
+    }
+
+    protected override void OnDataContextChanged(EventArgs e)
+    {
+        base.OnDataContextChanged(e);
+        if (DataContext is TagsViewModel tags && !_registered)
+        {
+            _registered = true;
+            tags.AddTag.RegisterHandler(_ => EditTagAsync(tags, null));
+            tags.EditTag.RegisterHandler(item => EditTagAsync(tags, item));
+            tags.DeleteTag.RegisterHandler(item => DeleteTagAsync(tags, item));
+        }
+    }
+
+    /// <summary>Gets the window that owns this view, used as the dialog owner.</summary>
+    private Window? OwningWindow => TopLevel.GetTopLevel(this) as Window;
+
+    /// <summary>Shows the add/edit tag dialog and refreshes on success.</summary>
+    private async Task EditTagAsync(TagsViewModel tags, TagItemViewModel? item)
+    {
+        if (OwningWindow is not Window owner)
+        {
+            return;
+        }
+
+        var dialog = new TagEditorDialog
+        {
+            DataContext = new TagEditorViewModel(tags.Repository, item?.Tag),
+        };
+        if (await dialog.ShowDialog<bool>(owner))
+        {
+            tags.RefreshAfterChange();
+        }
+    }
+
+    /// <summary>Confirms and deletes a tag, then refreshes.</summary>
+    private async Task DeleteTagAsync(TagsViewModel tags, TagItemViewModel item)
+    {
+        if (OwningWindow is not Window owner)
+        {
+            return;
+        }
+
+        bool confirmed = true;
+        if (App.Services?.Config.Confirmations.DeleteTag == true)
+        {
+            var dialog = new DeleteTagConfirmDialog
+            {
+                DataContext = new DeleteTagConfirmViewModel(item.Name, item.UsageCount),
+            };
+            confirmed = await dialog.ShowDialog<bool>(owner);
+        }
+
+        if (!confirmed)
+        {
+            return;
+        }
+
+        tags.Repository.DeleteTag(item.Tag.Id);
+        tags.RefreshAfterChange();
+    }
+}

YKanBan/Views/WorkspaceView.axaml

@@ -4,6 +4,7 @@
              xmlns:lang="using:YKanBan"
              xmlns:icons="using:IconPacks.Avalonia.Lucide"
              xmlns:board="using:YKanBan.Views.Board"
+             xmlns:tags="using:YKanBan.Views.Tags"
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="d" d:DesignWidth="1000" d:DesignHeight="640"
@@ -27,7 +28,7 @@
                 </StackPanel>
 
                 <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="8" VerticalAlignment="Center">
-                    <Button Command="{Binding ExportCommand}">
+                    <Button Command="{Binding RunExportCommand}">
                         <StackPanel Orientation="Horizontal" Spacing="6">
                             <icons:PackIconLucide Kind="FileDown" Width="16" Height="16"/>
                             <TextBlock Text="{x:Static lang:Resources.Main_Export}"/>
@@ -54,7 +55,9 @@
             <TabItem Header="{x:Static lang:Resources.Tab_Board}">
                 <board:BoardView DataContext="{Binding Board}"/>
             </TabItem>
-            <TabItem Header="{x:Static lang:Resources.Tab_Tags}"/>
+            <TabItem Header="{x:Static lang:Resources.Tab_Tags}">
+                <tags:TagsView DataContext="{Binding Tags}"/>
+            </TabItem>
         </TabControl>
 
     </Grid>

YKanBan/Views/WorkspaceView.axaml.cs

@@ -1,11 +1,79 @@
+using System.Text;
 using Avalonia.Controls;
+using Avalonia.Platform.Storage;
+using YKanBan.Export;
+using YKanBan.ViewModels;
+using YKanBan.ViewModels.Dialogs;
+using YKanBan.Views.Dialogs;
+using Resx = YKanBan.Resources;
 
 namespace YKanBan.Views;
 
 public partial class WorkspaceView : UserControl
 {
+    private bool _registered;
+
     public WorkspaceView()
     {
         InitializeComponent();
     }
+
+    protected override void OnDataContextChanged(EventArgs e)
+    {
+        base.OnDataContextChanged(e);
+        if (DataContext is WorkspaceViewModel viewModel && !_registered)
+        {
+            _registered = true;
+            viewModel.Export.RegisterHandler(ExportAsync);
+        }
+    }
+
+    /// <summary>Prompts for a file and writes the Markdown board export to it.</summary>
+    private async Task ExportAsync(Unit input)
+    {
+        if (DataContext is not WorkspaceViewModel viewModel)
+        {
+            return;
+        }
+        if (TopLevel.GetTopLevel(this)?.StorageProvider is not { } storage)
+        {
+            return;
+        }
+
+        DateTimeOffset exportedAt = DateTimeOffset.Now;
+        IStorageFile? file = await storage.SaveFilePickerAsync(new FilePickerSaveOptions
+        {
+            Title = Resx.Main_Export,
+            SuggestedFileName = MarkdownExporter.BuildFileName(viewModel.WorkspaceName, exportedAt),
+            DefaultExtension = "md",
+            FileTypeChoices = [new FilePickerFileType("Markdown") { Patterns = ["*.md"] }],
+        });
+        if (file is null)
+        {
+            return;
+        }
+
+        var repository = viewModel.Session.Repository;
+        string markdown = MarkdownExporter.Export(
+            viewModel.WorkspaceName,
+            repository.GetColumns(),
+            repository.GetCards(),
+            repository.GetTagsWithUsage(),
+            exportedAt);
+
+        await using (Stream stream = await file.OpenWriteAsync())
+        await using (var writer = new StreamWriter(stream, new UTF8Encoding(encoderShouldEmitUTF8Identifier: false)))
+        {
+            await writer.WriteAsync(markdown);
+        }
+
+        if (TopLevel.GetTopLevel(this) is Window owner)
+        {
+            var dialog = new ExportDoneDialog
+            {
+                DataContext = new ExportDoneViewModel(file.TryGetLocalPath() ?? file.Name),
+            };
+            await dialog.ShowDialog(owner);
+        }
+    }
 }

YKanBan/YKanBan.csproj

@@ -39,7 +39,6 @@
   <ItemGroup>
     <PackageReference Include="Avalonia" Version="11.3.6" />
     <PackageReference Include="Avalonia.Desktop" Version="11.3.6" />
-    <PackageReference Include="Avalonia.Themes.Fluent" Version="11.3.6" />
     <PackageReference Include="Avalonia.Fonts.Inter" Version="11.3.6" />
     <!--Condition below is needed to remove Avalonia.Diagnostics package from build output in Release configuration.-->
     <PackageReference Include="Avalonia.Diagnostics" Version="11.3.6">
@@ -48,6 +47,7 @@
     </PackageReference>
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.2.1" />
     <PackageReference Include="Semi.Avalonia" Version="11.2.1.10" />
+    <PackageReference Include="Semi.Avalonia.ColorPicker" Version="11.2.1.10" />
     <PackageReference Include="IconPacks.Avalonia.Lucide" Version="2.0.0" />
     <PackageReference Include="Microsoft.Data.Sqlite" Version="9.0.20" />
     <PackageReference Include="Pidgin" Version="3.5.1" />