What a drag: Dragging a Uniform Resource Locator (URL)
Last time, we dragged some text around
and found that the text would be interpreted as a URL if you
dropped it onto Firefox,
but Internet Explorer was not as willing to accept it.
Today, we'll make the data object work for Internet Explorer.
The only change is that we have to provide the URL in the
form of a CFSTR_SHELLURL clipboard format
rather than as CF_TEXT.
Take the program from last time and make two changes.
First, use the handy-dandy search-and-replace function to
change DATA_TEXT to DATA_URL
throughout.
(This step isn't technically necessary, but it's nice to have
the name match its usage.)
The real work happens in this change to the constructor:
CTinyDataObject::CTinyDataObject() : m_cRef(1)
{
SetFORMATETC(&m_rgfe[DATA_URL],
RegisterClipboardFormat(CFSTR_SHELLURL));
}
That's all; just change the clipboard format from
CF_TEXT to CFSTR_SHELLURL.
It is important to note that CFSTR_SHELLURL
represents an ANSI string.
Since
"URLs
are written only with the graphic printable characters
of the US-ASCII coded character set,"
there is no loss of expressiveness by restricting to ANSI.
Run this new program and now you can click in the client area
and drag/drop the (invisible) object onto Internet Explorer,
where it will navigate to Microsoft's home page.
(If your system supports Active Desktop, you can also drag/drop
the invisible object to the desktop and create an Active Desktop component.)
Okay, so we have one version of the program that can drag
a URL to Internet Explorer, and another version that can
drag a URL to FireFox.
Next time, we'll combine them to have a single data object
that can drop to both.
It's quite embarrassingly simple (because I planned it that way).
