Dear List

This posting links to a question asked yesterday regarding
WinChangedHandler.

I am writing code that will "on the fly" extract an "area of interest"
from a very large data holding (58 GB). The code now works really well
in Version 8.0 of MapInfo. However the same code makes version 6.5 of
MapInfo crash.

My concern is will the code work in future versions of MapInfo.

The process I have written must be very similar to how MapInfo "draws"
from Oracle spatial. I use the WinChangedHandler to call a C DLL that
rewrites any tables that appear in the current map window. On exit from
the WinchangedHandler the new layers exist .Time taken is under 1 second
for a  1 km width. At 500 metre map width,  its too quick to time.

What appears to happen is that MapInfo 6.5 carries on "checking" for
existance of tables. So if the WinChangedHandler overwrites the table it
crashes. Actually it only crashes if the FIND is used to recentre the
map ( search done from table NOT being overwritten ). Even in 6.5 all
other map movement - ie zoom, pan and change view work ok.

In version 8.0 all methods work, but I do need a print statement at the
end of the WinchangedHandler. Its as if this print allows MapInfo to
"catch up" with itself. If the print is not there, then the map window
stays blank. A redraw puts it right. If I put the redraw in place of the
print, it does not work.

Has anybody reading this posting done anything similar. I am so close to
a final solution, but I cannot leave it printing a line into the message
window. Also, without understanding the difference between 6.5 and
version 8.0, I am worried about support going forward.


Regards



Bob Young
@MapsByDesign.co.uk

-- 
bob young
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