What a drag: You can be a drag in managed code, too

November 13, 2009 Nov 13, 2009 11/13/09

Raymond Chen

David Anson digests my earlier series on virtual drag/drop and translates it into managed code. His example of dragging his entire RSS feed is an excellent illustration of dragging dynamically-generated virtual content. (I didn't use an example like that because the purpose of the What a drag series was to get something done in the least ...

You can drag multiple virtual objects, you know

March 31, 2008 Mar 31, 2008 03/31/08

Raymond Chen

A customer wanted to know how they could find out the directory that the user dropped a file onto. As we already noted, users can drop files onto things other than directories, so the question itself comes with incorrect hidden assumptions. This is another one of those cases where you have to ask the customer, "What are you really trying to ...

What a drag: Dragging a virtual file (IStorage edition)

March 20, 2008 Mar 20, 2008 03/20/08

Raymond Chen

There are three storage media that can be used for virtual file transfer. We've already seen HGLOBAL and IStream; the last one is IStorage. I doubt anybody will ever need to do virtual file transfer with structured storage, but here it is anyway. Remember that the theme of this series is "It's the least you can do", so I'm going to try to ...

What a drag: Dragging a virtual file (IStream edition)

March 19, 2008 Mar 19, 2008 03/19/08

Raymond Chen

Last time, we saw how to drag a virtual file whose contents are expressed as a block of bytes in memory (HGLOBAL). Often, a block of bytes is not a convenient way to express the contents of a virtual file. You might prefer to express it as a stream. For example, the contents might be dynamically generated (say by the output of an algorithm...

What a drag: Dragging a virtual file (HGLOBAL edition)

March 18, 2008 Mar 18, 2008 03/18/08

Raymond Chen

Now that we've gotten our feet wet with simple data objects, let's do something a smidge more complicated but extremely useful: Dragging a virtual file. There are many ways of doing this, but I'll start with the simplest one, where the virtual file is represented as a block of memory. Remember, the subtitle of this series is "It's the ...

What a drag: Dragging a Uniform Resource Locator (URL) and text

March 13, 2008 Mar 13, 2008 03/13/08

Raymond Chen

We've learned how to drag text and how to drag a uniform resource locator, but what if want to drag both? Well, it's actually a simply matter of saying that you have both (and actually producing it on demand). Start by extending the enumeration of data types to include both URL and text: There is a subtlety in the way we set up this ...

What a drag: Dragging a Uniform Resource Locator (URL)

March 12, 2008 Mar 12, 2008 03/12/08

Raymond Chen

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...

What a drag: Dragging text

March 11, 2008 Mar 11, 2008 03/11/08

Raymond Chen

This week's mini-series was almost titled "It's the least you could do" because I'm going to try to do the absolute least amount of work to accomplish something interesting with drag and drop. The real purpose today is to lay some groundwork, but just to have something to show for our effort, I'll show you how to drag text around. We're ...