Markdown → HTML
StringBuilder.MarkdownToHtml

The Method

One call, two modes

The MarkdownToHtml method lives on Chilkat's StringBuilder class. It reads the Markdown held by the object and writes HTML into a destination StringBuilder. A single JSON options argument controls themes, syntax highlighting, streaming, and document structure.

public bool MarkdownToHtml(JsonObject options, StringBuilder sbHtml);

How it behaves

Full document vs. streaming

Presentation

Built-in themes

Select a predefined theme when creating a shell or converting in non-streaming mode. Or leave it empty for the default full-document output.

Configuration

The options JSON

Everything is driven by keys in the options JsonObject. v11.2.0 and v11.3.0 mark when each key was introduced.

Quick start

Full document, default

An empty options object produces a complete HTML document — doctype, head, body, and all.

// Leaving the options empty produces a full HTML document.
Chilkat.JsonObject options = new Chilkat.JsonObject();

Chilkat.StringBuilder sbMarkdown = new Chilkat.StringBuilder();
Chilkat.StringBuilder sbHtml = new Chilkat.StringBuilder();

sbMarkdown.LoadFile("qa_data/markdown/test1.md", "utf-8");

sbMarkdown.MarkdownToHtml(options, sbHtml);
sbHtml.ToCRLF();

Debug.WriteLine(sbHtml.GetAsString());

Streaming mode

Feed Markdown in chunks — exactly how AI deltas arrive. Each call appends whatever complete lines it can, and returns the rest to the buffer.

Chilkat.JsonObject options = new Chilkat.JsonObject();
options.UpdateString("theme", "raw");
options.UpdateBool("streaming", true);

// sbStreamingMarkdown holds Markdown not yet converted.
// Append each incoming chunk, then convert what's possible.
while (sbFullMarkdown.Length > 0) {
    string chunk = sbFullMarkdown.GetRange(0, 80, true);
    sbStreamingMarkdown.Append(chunk);

    sbHtmlFrag.Clear();
    sbStreamingMarkdown.MarkdownToHtml(options, sbHtmlFrag);  // appends new HTML
    sbHtml.AppendSb(sbHtmlFrag);
}

// Flush remaining closing tags with a final newline.
sbStreamingMarkdown.Append("\n");
sbHtmlFrag.Clear();
sbStreamingMarkdown.MarkdownToHtml(options, sbHtmlFrag);
sbHtml.AppendSb(sbHtmlFrag);

New in v11.3.0

Real-time streaming to embedded browsers

LLMs like GPT-4 emit rich Markdown token-by-token. Instead of making users wait for the whole answer, Chilkat acts as an intelligent bridge — parsing incoming Markdown as a state machine and translating it directly into JavaScript calls that update an embedded browser (or WebView) as the AI "thinks."

How it flows

By dynamically adjusting the CSS selector (for example div.response-content:last-of-type > ol:last-child), Chilkat builds complex, correctly-nested HTML in real time — letting users watch the answer format itself line by line instead of staring at a spinner.

Sample code

Markdown examples

Complete, runnable examples — shown here in C#, and available in 30+ languages.

See all Markdown examples →

Write once, everywhere

The same API in every language

StringBuilder.MarkdownToHtml is identical across all Chilkat-supported languages and platforms — the C# examples on this page translate directly.