Generating Dynamic HTML in .NET: A Reliable Approach Using WebBrowser and mshtml.HTMLDocument

Dynamic HTML generation is a frequent requirement in web development. .NET offers several tools for this, including the System.Windows.Forms.WebBrowser class and the mshtml.HTMLDocument COM interface (from the Microsoft HTML Object Library).

Using the WebBrowser Class

The WebBrowser class typically allows navigation to a URL and retrieval of the rendered HTML. However, it doesn't always provide the fully rendered HTML because the rendering process might not be complete. To address this, monitor the DocumentCompleted event; retrieve the HTML only after this event fires.

The mshtml.HTMLDocument Interface

The mshtml.HTMLDocument interface offers direct manipulation of rendered HTML. You can use the write method to navigate to a URL and iterate through the all collection to obtain the HTML. However, this method may not always reflect the final rendered HTML accurately, potentially differing from the raw HTML.

A More Robust Solution: Combining Both Methods

A superior approach combines the strengths of both methods. Use WebBrowser for navigation and mshtml.HTMLDocument for HTML retrieval, ensuring complete rendering before retrieval. This involves:

1. Navigating to the URL via WebBrowser.
2. Tracking rendering completion using the DocumentCompleted event.
3. Obtaining the mshtml.IHTMLDocument2 interface from WebBrowser.
4. Iterating through the all collection of mshtml.IHTMLDocument2 to retrieve the fully rendered HTML.

This combined method offers a reliable way to get dynamically generated HTML using .NET's WebBrowser and mshtml.HTMLDocument. For accurate rendering, consider enabling HTML5 rendering through Browser Feature Control.