Added July 2021
xcall MIAMEX, MX_DRAGDROP, opcode, status, ctlid {,fidx ,fspec}
MX_DRAGDROP (MIAMEX 199) provides support for accepting files dragged and dropped from Windows File Explorer—or another Windows Shell object—onto a control created with AUI_CONTROL.
This function has both a subroutine and a print tab implementation.
To enable the feature, specify the WS_EX_ACCEPTFILES (&h0010) flag in the winstylex parameter of the AUI_CONTROL call when creating the target control. Typically this would be a static control, perhaps with a colored background and some explanatory text (e.g. “"Drop files here"), but in theory it could be nearly any control type—including dialogs—that are created with AUI_CONTROL.
Two modes are supported: destructive and non-destructive. In the destructive mode, each drop event replaces the existing contents of the drop buffer with the newly dragged file specs, as with a clipboard Copy. In the non-destructive mode, each drop event adds to the existing contents of the drop buffer. Destructive mode is the default. Non-destructive mode is established via MX_DRAGDROP opcode 3 after creating the drop target control.
In both modes, the drop event triggers exitcode -75,notifying the application so that it can respond by querying and/or retrieving the filespecs using the MX_DRAGDROP function.
Parameters
opcode (Num) [in]
Value |
Description |
---|---|
0 |
query drop buffer, set status parameter to the number of files in the drop target (ctlid) |
1 |
retrieve fspec corresponding to fidx from the specified drop target (ctlid) |
2 |
clear the contents of the drop target buffer |
3 |
set non-destructive (previous "asynchronous") mode |
status (Signed Num) [out]
<=0: failure, or no files available in opcode 0; >0: success, which is the number of files for opcode 0, or the number of bytes in fspec for opcode 1
ctlid (String ) [in]
control id of the target control
fidx (Num) [in]
for opcode 1, must be set to the number of the fspec to retrieve (starting with 1)
fspec (String ) [out]
file specification returned for opcode 1
Comments
Note that it isn’t actually the files themselves that are being dragged and dropped; it is just their file specifications.
Although the implementation is primarily on the Windows side, accessing the new MX_DRAGDROP feature from an ATE session will require that the server instance of A-Shell also be at least at version 6.5.1705.
There is nothing stopping you from defining more than one drop target control within a given UI context. But since all drop events trigger the same exitcode -75, you would need to query each of the possible drop target controls in order to identify which control received the drop event.
Examples
Create a drop target control—in this case, a static text control. The critical element here is the WS_EX_ACCEPTFILES value for the winstylex parameter.…
! create the drop target (must be MBF_STATIC with WS_EX_ACCEPTFILES)
DROPCTLID$ = “txtDropTarget”
xcall AUI, AUI_CONTROL, CTLOP_ADD, DROPCTLID$, &
"Drop File(s) Here" + chr(13) + "Click to query", MBST_ENABLE, &
MBF_STATIC+MBF_CENTER+MBF_KBD, "VK_xF100", NUL_FUNC$, NUL_CSTATUS, &
srow,scol,erow,ecol, NUL_FGC, &hddccbb, &
NUL_FONTATTR, NUL_FONTSCALE, NUL_FONTFACE$, NUL_TOOLTIP$, &
DLGID$, NUL_WINCLASS$, NUL_WINSTYLE, WS_EX_ACCEPTFILES, &
NUL_CTYPE2
Set asynchronous mode:
opcode = 3
ctlid = DROPCTLID$
xcall MIAMEX, MX_DRAGDROP, opcode , status, ctlid
Query drop target to see how many files are available:
opcode = 0
ctlid = DROPCTLID$
xcall MIAMEX, MX_DRAGDROP, opcode , status, ctlid
count = status ! # of files in target
Retrieve file specifications from the drop target:
opcode = 1
ctlid = DROPCTLID$
for fidx = 1 to count ! count retrieved from opcode 0
xcall MIAMEX, MX_DRAGDROP, opcode, status, ctlid, fidx, fspec$
? “File #”;fidx;” : “;fspec$
next fidx
Also See
• | The sample program FILEDROP1.BP in EXLIB:[908,90] illustrating a simple drag-drop user interface. |
History
2021 July, A-Shell 6.5.1705: Function added to A-Shell.