DocumentToolBar — ParentElement RichTextKit

Overview

DocumentToolBar is an Avalonia UserControl that wraps all common formatting actions. It subscribes to RichTextEditor.SelectionInfo and automatically updates its toggle states (bold, italic, alignment buttons, etc.) as the user moves the caret or changes the selection.

Wire it by setting the Editor property to a RichTextEditor instance. This is typically done in your window's OnInitialized() or OnLoaded().

AXAML Usage

<DockPanel>
    <pe:DocumentToolBar
        x:Name="Toolbar"
        DockPanel.Dock="Top"
    />
    <pe:RichTextEditor
        x:Name="Canvas"
    />
</DockPanel>

// In code-behind
protected override void OnInitialized()
{
    base.OnInitialized();
    Toolbar.Editor = Canvas;
}

Properties

Property	Type	Description
Editor	RichTextEditor	The linked editor. Setting this wires up all event subscriptions. Always set this before the user interacts with the toolbar. This is an Avalonia Direct property — bindable.
SelectionInfo	SelectionInfo	Reflects the current selection state (alignment, list type, list level, line spacing). Updated automatically when the editor fires `OnNavigation`. Bindable Direct property — useful for binding toggle states in custom toolbars.

Toolbar Controls

The toolbar is initialized during construction and includes the following controls:

Font & Size

Control	Action
Font Family ComboBox	Populated from `FontManager.Current.SystemFonts`. Selection calls `ApplyFontFamily()`.
Font Size ComboBox	Sizes: 8, 9, 10, 11, 12, 14, 16, 18, 20, 24, 28, 32, 36, 48, 60, 72, 80 pt. Selection calls `ApplyFontSize()`.

Style Toggles

Button	Shortcut	Action
Bold (B)	Ctrl+B	`DocumentController.ApplyBold()`
Italic (I)	Ctrl+I	`DocumentController.ApplyItalic()`
Underline (U)	Ctrl+U	`DocumentController.ApplyUnderline()`
Strikethrough (S)	—	`DocumentController.ApplyStrikethrough()`
Subscript (X₂)	—	`DocumentController.ApplySubscript()`
Superscript (X²)	—	`DocumentController.ApplySuperscript()`

Color

Control	Action
Text Color button	Opens color picker → `DocumentController.ApplyFontColor(color)`
Highlight Color button	Opens color picker → `DocumentController.ApplyBackgroundColor(color)`

Paragraph Alignment

Button	Action
Align Left	`ApplyAlignment(TextAlignment.Left)`
Align Center	`ApplyAlignment(TextAlignment.Center)`
Align Right	`ApplyAlignment(TextAlignment.Right)`
Justify	`ApplyAlignment(TextAlignment.Justified)`

Lists & Indent

Button	Action
Bullet List	`DocumentController.ToggleBulletList()`
Numbered List	`DocumentController.ToggleNumberedList()`
Indent More	`DocumentController.AdjustParagraphIndent(+20)`
Indent Less	`DocumentController.AdjustParagraphIndent(-20)`

Line Spacing

Dropdown with preset multipliers: 1.0, 1.15, 1.5, 2.0, 2.5, 3.0

Document Settings

Button opens DocumentSettingsDialog. Changes are applied via DocumentController.ApplyDocumentSettings().

Import & Export Methods

These methods can be called programmatically (e.g., from a menu handler) in addition to the built-in toolbar buttons.

Method	Description
`async Task ImportHtml()`	Opens file picker, imports HTML via `HtmlImporter`, replaces document content
`async Task ImportRtf()`	Opens file picker, imports RTF via `RtfImporter`
`async Task ImportDocx()`	Opens file picker, imports DOCX via `OpenXmlImporter`
`async Task ExportHtmlFile()`	Opens save picker, exports via `HtmlExporter.ExportAsync(stream)`
`async Task ExportRtfFile()`	Opens save picker, exports via `RtfExporter.ExportAsync(stream)`
`async Task ExportDocxFile()`	Opens save picker, exports via `OpenXmlExporter.ExportAsync(stream)`
`async Task InsertImage()`	Opens file picker for PNG/JPEG/BMP, calls `DocumentController.InsertInlineImage()`
`async Task MenuCopy()`	`DocumentController.Copy()`
`async Task MenuCut()`	`DocumentController.Cut()`
`async Task MenuPaste()`	`DocumentController.Paste()`

// Call import/export programmatically (e.g., from a custom menu)
private async void MenuImport_Click(object sender, RoutedEventArgs e)
{
    await Toolbar.ImportDocx();
}

private async void MenuExport_Click(object sender, RoutedEventArgs e)
{
    await Toolbar.ExportHtmlFile();
}

Automatic Selection Synchronization

When Editor is set, DocumentToolBar subscribes to the editor's DocumentController.OnNavigation event and updates all its control states — toggle buttons, font/size dropdowns, color displays — to match the style at the caret.

A _updatingToolbar guard flag prevents feedback loops where a toolbar update would fire a selection-changed event that triggers another update.