Board index » cppbuilder » Dragging on an TImage

2006-12-16 10:47:59 AM
cppbuilder106
I want to drag image files from the explorer on a TImage component and
resolve the filename of the files dropped.
To start I set e Breakpoint on the OnDragOver-method. But the program never
reaches this breakpoint.
1. What am I doing wrong?
2. How do I get the filename(s) once this works?
Regards
 

"Stefan" < XXXX@XXXXX.COM >wrote:
names but TImage does not descend from TWinControl so it
doesn't have a HWND (Handle) that is needed to be used
with a call to the Win32 API DragAcceptFiles. You might
consider using a TPanel instead.
Once you call DragAcceptFiles, to get the file names,
you first need to recieve notification in the form of a
WM_DROPFILES message. This would require that you subclass
the control's WindowProc method or subclass the control
and override it's WndProc method *or* use a message map.
If you use a TPanel v/s a TImage, you can also override it's
Paint method to display the image.
To process the WM_DROPFILES, all you need is a simple block of
code that looks something like:
HDROP hDrop = reinterpret_cast<HDROP>( Message.WParam );
int FileCount = DragQueryFile( hDrop, -1, NULL, 0 );
for( int x = 0; x < FileCount; ++x )
{
int CharCount = DragQueryFile( hDrop, x, NULL, 0 );
char *FileName = new char[ CharCount + 1 ];
DragQueryFile( hDrop, x, FileName, CharCount + 1 );
// use FileName
delete [] FileName;
}
DragFinish( hDrop );
~ JD