Re: shell32: Bind to correct drop target after drag scrolling

[Michael Jung]

Hi Alexandre,

seems like you rejected this patch. Is it too hack'ish? At a first glance it 
seems like it would be enough to figure out the IDropTarget belonging to the 
hwnd and call a DragOver on this interface. The problem is that the drop 
source (or the DoDragDrop function) might have to change the cursor.

Could you please give me a tip on how to do this the right way?

Index: dlls/shell32/shlview.c
===================================================================
RCS file: /home/wine/wine/dlls/shell32/shlview.c,v
retrieving revision 1.123
diff -u -p -r1.123 shlview.c
--- dlls/shell32/shlview.c	2 Dec 2005 13:14:58 -0000	1.123
+++ dlls/shell32/shlview.c	2 Dec 2005 16:44:38 -0000
@@ -2190,6 +2190,8 @@ static ULONG WINAPI ISVDropTarget_Releas
 #define IDT_RIGHT 0x8u

VOID CALLBACK scroll_timer_proc(HWND hwnd, UINT uMsg, UINT_PTR idTimer, DWORD 
dwTimer) {
+    INPUT input;
+
     switch (idTimer) {
         case IDT_UP:
             SendMessageW(hwnd, WM_VSCROLL, SB_LINEUP, 0);
@@ -2204,6 +2206,14 @@ VOID CALLBACK scroll_timer_proc(HWND hwn
             SendMessageW(hwnd, WM_HSCROLL, SB_LINEDOWN, 0);
             break;
     }
+
+    /* The cursor might now hover over a different item in the listview than
+     * prior to the scrolling. Send a dummy mouse event (with a (x=0, y=0)
+     * relative movement) to initiate the apropriate Drag & Drop calls. */
+    ZeroMemory(&input, sizeof(input));
+    input.type = INPUT_MOUSE;
+    input.u.mi.dwFlags = MOUSEEVENTF_MOVE;
+    SendInput(1, &input, sizeof(input));
 }

/******************************************************************************

Bye,

shell32: Bind to correct drop target after drag scrolling

[Alexandre Julliard]

Michael Jung  writes:
> Hi Alexandre,
>
> seems like you rejected this patch. Is it too hack'ish? At a first glance it 
> seems like it would be enough to figure out the IDropTarget belonging to the 
> hwnd and call a DragOver on this interface. The problem is that the drop 
> source (or the DoDragDrop function) might have to change the cursor.
>
> Could you please give me a tip on how to do this the right way?

I don't really know what the right way is, I just know that faking
mouse messages probably isn't it <g>

shell32: Bind to correct drop target after drag scrolling

[Michael Jung]

Hi,

On Tuesday 06 December 2005 00:26, Alexandre Julliard wrote:
> I don't really know what the right way is, I just know that faking
> mouse messages probably isn't it <g>

You were right (of course ;-) Attached is a small test application, which 
supports the bare minimum to get drag & drop running. It traces all calls to 
the IDropTarget interface to a listbox. As it turns out WinXP calls DragOver 
approx. every 200ms while the mouse hovers over a registered DropTarget 
window (This makes it really easy for drop-targets to implement 
drag-scrolling). In addition DragOver is called after one of the 
drag-modifier-keys (shift+ctrl) is pressed or released. Wine doesn't do 
neither yet.

Is there any sensible way to transform this into a unit test? Or do we have a 
repository for this kind of small test applications, which are hard to 
implement as unit-tests?

Bye,