Introduction
This sample demonstrates using the new MFC7 CDHtmlDialog
class. A
dialog with a simple HTML page is created and displayed, and events
from objects within that page are handled, and the HTML within the
page modified dynamically to respond to these events.
Please note that you need the new MFC libraries to compile this application.
I have statically linked the demo application so you can at least see the new
class in action.
Creating the Application
The sample application is based on the MFC AppWizard. To create the
project, use the wizard to create a standard MFC dialog and in the
Application Type property page ensure that you choose dialog
based, and check the Use HTML dialog. An application will be
created with the main dialog derived from CDHtmlDialog
. A resource
containing a HTML page will also be created, and it's this page
that will be displayed in the dialog at execution.
The HTML designer in Visual Studio allows you to edit the HTML. Each
element on the HTML should be given an ID so that it can be accessed
from within your CDHtmlDialog
derived class.
HTML Element events
To catch events fired by HTML elements (such as mouse clicks on buttons)
you must add an entry to the dialog's DHTML event map. This is analogous
to adding message handlers for normal windows controls:
BEGIN_DHTML_EVENT_MAP(CDHTMLDialogDlg)
DHTML_EVENT_ONCLICK(_T("ButtonOK"), OnButtonOK)
DHTML_EVENT_ONCLICK(_T("ButtonCancel"), OnButtonCancel)
DHTML_EVENT_ONCLICK(_T("CheckLink"), OnCheckClick)
END_DHTML_EVENT_MAP()
Our HTML page contains 2 buttons (OK, with ID ButtonOK
and Cancel, with ID ButtonCancel
) and a checkbox (ID CheckLink
). We will use the checkbox
to enable/disable a hyperlink element (ID LinkCP
) on the same page.
The DHTML event map shown above associates click events for the buttons
and check boxes with member functions of the dialog. The OK and Cancel
button handlers simply call base class members that close the dialog. The
OnCheckClick handler is called when the checkbox in the HTML page is clicked.
To make the check box determine the state of the hyperlink we catch the click
event for the checkbox and replace the outer HTML of the hyperlink (the outer
HTML is the HTML within the hyperlink plus the open and closing tags). For
a non-active state we replace the out HTML with plain text, and for an active
state we insert the <a href=...>
tag.
Our click event handler function looks like the following. We use a member
variable m_LinkActive to keep track of the state of the link.
<a>HRESULT CDHTMLDialogDlg::OnCheckClick(IHTMLElement* pElement)
{
m_LinkActive = !m_LinkActive;
IHTMLElement* pLinkElement = NULL;
if (GetElement(_T("LinkCP"), &pLinkElement) == S_OK &&
pLinkElement != NULL)
{
if (m_LinkActive)
{
pLinkElement->put_outerHTML(_bstr_t("<a ID=LinkCP target=_blank href='http://www.codeproject.com'>here</a>"));
}
else
{
pLinkElement->put_outerHTML(_bstr_t("<font ID=LinkCP color='#COCOCO'>here</font>"));
}
pLinkElement->Release();
}
return S_OK;
}
</a>
Chris Maunder is the co-founder of
CodeProject, DeveloperMedia and ContentLab, and has been a prominent figure in the software development community for nearly 30 years. Hailing from Australia, Chris has a background in Mathematics, Astrophysics, Environmental Engineering and Defence Research. His programming endeavours span everything from FORTRAN on Super Computers, C++/MFC on Windows, through to to high-load .NET web applications and Python AI applications on everything from macOS to a Raspberry Pi. Chris is a full-stack developer who is as comfortable with SQL as he is with CSS.
In the late 1990s, he and his business partner David Cunningham recognized the need for a platform that would facilitate knowledge-sharing among developers, leading to the establishment of CodeProject.com in 1999. Chris's expertise in programming and his passion for fostering a collaborative environment have played a pivotal role in the success of CodeProject.com. Over the years, the website has grown into a vibrant community where programmers worldwide can connect, exchange ideas, and find solutions to coding challenges. Chris is a prolific contributor to the developer community through his articles and tutorials, and his latest passion project,
CodeProject.AI.
In addition to his work with CodeProject.com, Chris co-founded ContentLab and DeveloperMedia, two projects focussed on helping companies make their Software Projects a success. While at CodeProject, Chris' roles included Architecture and coding, Product Development, Content Creation, Community Growth, Client Satisfaction and Systems Automation, and many, many sales meetings. All while keeping his sense of humour.