MarkdownWPF

A high-performance Markdown renderer for WPF built on top of Markdig.

Instead of rendering everything into a heavy FlowDocument, MarkdownWPF generates lightweight WPF UI blocks (TextBlock, Border, Grid, etc.) and displays them via an ItemsControl with a VirtualizingStackPanel. This keeps scrolling smooth and memory usage reasonable even for large Markdown documents.

Features

• True UI virtualization
  Uses WPF virtualization (VirtualizingStackPanel + Recycling) so only visible blocks are realized in the visual tree.

• Markdig-based parsing
  Supports common Markdown and many GitHub-flavored extensions (depending on your Markdig pipeline).

• XAML-first styling & theming
  No hardcoded colors required. Override styles globally (App resources) or locally (UserControl/Window resources).

• Base-style override pattern
  Default styles are split into *Base + “working” styles, making it easy to inherit and override without circular BasedOn issues.

• Nested layout friendly spacing
  Optional “last-child margin” handling via an attached property + XAML triggers to avoid excessive gaps inside lists/quotes/tables.

• Image handling (layout + memory)
  Images are constrained to the viewer width (MaxWidth binding) to prevent horizontal overflow, and can be decoded with a configurable DecodePixelWidth to avoid huge RAM spikes when viewing large photos.

Installation

Install the preview package:

dotnet add package MarkdownWPF --prerelease

Or via Visual Studio: Manage NuGet Packages → enable Include prerelease → search for MarkdownWPF.

Quick start

1. Merge the default theme dictionary (recommended):

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="pack://application:,,,/MarkdownWPF;component/Themes/MarkdownDictionary.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

2. Use the control:

<Window
    xmlns:md="clr-namespace:MarkdownWPF;assembly=MarkdownWPF">

    <md:MarkdownViewer Markdown="{Binding MarkdownText}" />
</Window>

Customizing styles

All visuals are driven by standard WPF Style resources. You can override them:

• Globally in App.xaml, or
• Locally inside a UserControl.Resources / Window.Resources

The library is designed around a safe inheritance model:

• MarkdownParagraphStyleBase (base style)
• MarkdownParagraphStyle (working style used by the renderer)

To override a working style while keeping defaults:

<Window.Resources>
    <Style x:Key="MarkdownParagraphStyle"
           TargetType="TextBlock"
           BasedOn="{StaticResource MarkdownParagraphStyleBase}">
        <Setter Property="FontSize" Value="16"/>
        <Setter Property="Foreground" Value="DarkSlateGray"/>
    </Style>
</Window.Resources>

Notes / limitations

• SVG images: WPF does not render SVG out of the box. If your Markdown contains SVG badges (common in GitHub READMEs), you will need an SVG rendering library or a fallback strategy.
• This is a preview release: APIs, style keys, and render behavior may change.