Month: January 2005

Previously I talked about exposing the HTML editor hiding inside the WebBrowser control. I also talked about IOleCommandTarget and how you can control formatting and layout features of the editor. It won’t take long before you discover that the IOleCommandTarget command ID’s are somewhat limited. At some point, you will need to insert specialized text or HTML at the current cursor location or replacing the current selection. Luckily for us, there is an easy way to do it: IHTMLTxtRange.

I talked about IHTMLTxtRange in a previous post. It is useful for finding text or getting the text of the current selection. It can also do the reverse: It can insert text or HTML at the current cursor location or selection using the pasteHTML method. Here’s a simple example:

IHTMLDocument2* pDoc = ...;

IHTMLSelectionObject* pSelection = 0;
HRESULT hr = pDoc->get_selection(&pSelection);
if (SUCCEEDED(hr)) {
   IDispatch* pDispRange = 0;
   hr = pSelection->createRange(&pDispRange);
   if (SUCCEEDED(hr)) {
      IHTMLTxtRange* pTextRange = 0;
      hr = pDispRange->QueryInterface(IID_IHTMLTxtRange, (void**)&pTextRange);
      if (SUCCEEDED(hr)) {
         CComBSTR sText = L"This is <b>better</b> text";
         pTextRange->get_pasteHTML(sText);
         pTextRange->Release();
      }
      pDispRange->Release();
   }
   pSelection->Release();
}

pDoc->Release();

In the above example, the selection may have selected text or it may just be a cursor location. The HTML overwrites any selected text. Otherwise, it’s inserted at the cursor location.

Overall, IHTMLTxtRange is a very useful interface. I have used it for implementing spell check, find/replace and inserting complex HTML. Just to be clear, IHTMLTxtRange works when design mode is off or on. The WebBrowser control does not need to be in edit mode to call pasteHTML.

I have been posting about using MSHTML to display HTML-based content in your Windows applications. Some of the reasons I started doing this in my own code include:

• Easy way to create a modern looking task-based UI.
• Flexible and extensible, with a built-in script engine (JavaScript) and style system (CSS).
• Based on open standards

There is another interesting by-product:

• Very easy to allow end users to add their own custom HTML.

You’re running a full-blown web browser inside your application. All you need to do is provide some way for the user to specify their own URL. It could be from within the application UI or maybe a special registry key. You pass the URL to Navigate and their custom content appears in your application. What a great way to open your application to your end users.