I launched the script and obtained:
Drag some files and drop them on this window...then I dropped a file in the window and obtained:
You dropped 1 files.
at coordinate 63x313
1. /C/Documents and Settings/max/Desktop/Good day.pdf
Finishing drag operation
Unregistering window from DragAcceptFiles queueHere is the source code:
REBOL [
Title: "System Port - Drag Accept Demo"
File: %sys-port-drag-accept.r
Author: "Gregg Irwin"
EMail: greggirwin@acm.org
Version: 0.0.1
Date: 25-sep-2003
Purpose: {
Demo using system port to catch WM_DROPFILE messages for drag-n-drop
support.
}
]
; Stripped version of win-shell object for demo purposes.
win-shell: make object! [
win-lib: load/library %shell32.dll
null-buff: func [
{Returns a null-filled string buffer of the specified length.}
len [integer!]
][head insert/dup make string! len #"^@" len ]
drag-accept-files: make routine! [
hWnd [integer!]
fAccept [integer!]
return: [integer!]
] win-lib "DragAcceptFiles"
drag-finish: make routine! [
hDrop [integer!]
return: [integer!]
] win-lib "DragFinish"
point: make struct! [
x [integer!]
y [integer!]
] none
drag-query-point: make routine! compose/deep [
{Returns nonzero if the drop occurred in the client area of the window,
or zero if the drop did not occur in the client area of the window.}
hDrop [integer!]
lpPoint [struct! [(first point)]]
return: [integer!]
] win-lib "DragQueryPoint"
drag-query-file: make routine! [
hWnd [integer!]
iFile [integer!]
lpszFile[string!]
cb [integer!]
return: [integer!]
] win-lib "DragQueryFile"
drag-query-filename-size: make routine! [
hWnd [integer!]
iFile [integer!]
lpszFile[integer!]
cb [integer!]
return: [integer!]
] win-lib "DragQueryFile"
num-files-dropped?: func [hdrop [integer!]] [drag-query-file hdrop -1 "" 0 ]
; When they give us a filename index, we'll subtract one for them,
; because Windows has the list as zero based, but I'd much rather let
; everything be one based on the REBOL side.
dropped-filename-size?: func [
hdrop [integer!] index [integer!]
][drag-query-filename-size hdrop index - 1 0 0 ]
dropped-filename?: func [
hdrop [integer!] index [integer!] /local result len
][
result: null-buff add 1 dropped-filename-size? hdrop index
len: drag-query-file hdrop index - 1 result length? result
copy/part result len
]
]
my-hwnd?: does [second get-modes system/ports/system [window]]
WM_DESTROY: 2 ; &H2
WM_DROPFILES: 563 ; &H233
enable-system-trap: does [
; Trap OS interrupts
if not system/ports/system [
if none? attempt [system/ports/system: open [scheme: 'system]][print "NOTE: Missing System Port" exit ]
]
if find get-modes system/ports/system 'system-modes 'winmsg [
set-modes system/ports/system [winmsg: WM_DROPFILES]
]
append system/ports/wait-list system/ports/system
]
check-system-trap: func [port /local msg pt] [
if not port? port [return none]
if any [port/scheme <> 'system port <> system/ports/system][return port]
if not system/ports/system [return none]
while [msg: pick system/ports/system 1] [
;print ["msg:" mold msg]
if msg/1 = 'winmsg [
if msg/2 = WM_DROPFILES [
print [
"You dropped " win-shell/num-files-dropped? msg/3 "files."
]
pt: make struct! win-shell/point [0 0]
win-shell/drag-query-point msg/3 pt
print [" at coordinate " to pair! reduce [pt/x pt/y]]
repeat i win-shell/num-files-dropped? msg/3 [
file: to-rebol-file win-shell/dropped-filename? msg/3 i
print [
tab join i "." tab either dir? file [dirize file][file]
]
]
print "Finishing drag operation"
win-shell/drag-finish msg/3
print "Unregistering window from DragAcceptFiles queue"
win-shell/drag-accept-files my-hwnd? to integer! false
; (do something with files here)
halt
]
]
]
none
]
print "Drag some files and drop them on this window...^/"
win-shell/drag-accept-files my-hwnd? to integer! true
enable-system-trap
forever [
wake-port: wait []
if wake-port [check-system-trap wake-port]
]
