AutoHotkey Community

[rulfzid]

Here is some code I've been playing around with to make drag and drop worth within a Treeview control. The code is based off of the msdn documentation of drag&drop in TV controls here:

I've documented the script pretty thoroughly, so a lot of the information is in there, but some things of note:

• No drag image - I point out in the comments where the code for the dragimage stuff should go, but decided not to include it because it was being buggy and because I frankly prefer the method I ended up going with (drop target highlighting and insertion marks)
  
• Drop handling - my focus was on the getting the dragging stuff to work, which I did. What to do when the dragging ends is something I contended with only in a very simple way (just added the dragged node as a child of the drop target). There are other things one could do - vary the drop action depending on what kind of drop target / drag item you were contending with, etc.

Anyway, here's the code:

[Drugwash]

One innocent question: what happens if the script this function is supposed to go with, already has its own OnMessage handlers that clash with your function's?

What I've been working on the past few days is Hotkey/KeyWait alternatives for Win9x (since the built-in functions don't work on such systems and I'm running 98SE) and I've also used OnMessage, but tried to make it into generic handlers.

What I mean is, the OnMessage functions would set a flag for each particular message received and the rest of the functions/script would act according to those flags.

What I couldn't resolve is passing a dynamic variable from function to function without creating a set of global variables. Tried to use NumPut/NumGet to save/retrieve the variable addresses but failed.

Anyway, I hope this helps somehow. The idea is good.

[rulfzid]

@Drugwash

The initial way I handled this was to (not sure if i'm using terminology correctly, but you'll get the idea) subclass the window procedure, a la:

[Drugwash]

Ah, this may still be better than "stealing" mouse movement messages.
I must confess though, that my understanding of subclassing is quite limited (being just a nosy amateur, not a programmer). Hopefully the titans of AHK will chime in with some good, working suggestions.

[Charon the Hand]

Very well done, rulfzid; I'm glad you shared this. I was banging my head against a wall trying to write these functions myself and couldn't wrap my brain around the recursion. My add node functions were ludicrously long and filled with arcane symbols to denote depth in the tree. Ugh. All replaced by a few simple lines, thank you very much.

As a side note, I've gotten reports from some of my users that my program doesn't behave well when there is a message handler, so I rewrote the drag section to just use a while loop. It works seemingly identically and makes me feel like I've done some work. This function is fired by the treeview g-label if A_EventInfo = D (drag attempt). Maybe this could help Drugwash a few posts up, since no message handlers are needed for this version.

[Deo]

thanks guys, this is really great example

[Drugwash]

I've added this functionality to SmartGUI Creator Mod but it's not at all optimized for StdLib functionality. It does however implement drag image but it's by no means complete, nor bug-free. May still be a source of inspiration for others, though.