Mshtml

We can’t discuss embedding WebBrowser in an application without also discussing IDocHostUIHandler. The IDocHostUIHandler (and IDocHostShowUI) interface is the standard method provided by Microsoft for customizing how WebBrowser works when hosted in an application. Some of the things you can use IDocHostUIHandler to do include:

Did you know that you can turn WebBrowser into a decent WYSIWYG HTML editor? It’s true and it’s relatively simple. There are actually two ways to turn on the editor mode: contentEditable markup attribute, and IHTMLDocument2::designMode method. Since we are talking about embedding WebBrowser in an application, the IHTMLDocument2::designMode method is the most typical choice.

In this post I wanted to cover some miscellaneous things you may want to do with your embedded WebBrowser. On its own, the IWebBrowser2 interface does not support doing much more than we already covered in previous posts. However, if you start using the MSHTML DOM interfaces, much more functionality is available. Here is a list of simple things you can implement without too much difficulty:

Before moving ahead with the MSHTML hosting posts, I wanted to take a moment to talk about alternatives to WebBrowser. I am sure you are familiar with the Mozilla webbrowser. Started as an open source project by Netscape, Mozilla and its suite of companion projects are quite an achievement. One of the Mozilla projects is an ActiveX wrapper around the rendering engine which conforms to the IWebBrowser2 and DWebBrowserEvents2 COM interfaces. Created and maintained by Adam Lock the project has come along way. There is even minimal support for the IHTMLDocument DOM interfaces.

My last posts have dealt with using the WebBrowser component to display HTML pages inside your application. We have seen how it does not take much to embed the control to create your own little mini-webbrowser. In this post I want to go a little further than building a webbrowser. Lots of applications are using a web-like UI. Applications like Intuit Quicken, Microsoft Outlook and Money actually use the WebBrowser control to achieve their web-like UI’s. Microsoft Office task panes and other inductive UI’s can be developed using the WebBrowser control.

On the surface it seems like a great deal. You can actually embed MSHTML, the IE HTML rendering engine, in your own application. There is a lot of cool, simple features you get out-of-the-box. As soon as you get more advanced in your features, you find things are not so simple.

Hosting IE in your application is a relatively straight forward process, provided your development environment supports the use of ActiveX controls. Each language/framework has its own way of doing it: VB works directly with the WebBrowser control, MFC has its CHtmlView wrapper classes, Delphi has the TWebBrowser wrapper and C++Builder uses TCppWebBrowser. Create one of these somewhere in your application and your on your way to displaying HTML pages.