Am 27.11.2017 um 13:43 schrieb Torsten Bonde Christiansen via Lazarus:
I am looking for grid component that can display string. Simple
enought and i know of a few already, but the ones i know of cannot do
both of the following requirements i have:
a) Fast (very low delay on 100.000+ lines of test)
b) Allow selecting multiple cells spanning rows and colomns.
For a) i know of VirtualTreeview which handles large data very very
fine. The problem is that is does not allow for selecting multiple
columns and rows combined.
For b) there is the native LCL stringgrid, the lazarus package
TKontrols is also good, but they don't handle large data very well.
Mostly because all rows/columns are traversed (initialized) instead of
the just the actual rows/columns displayed onscreen.
(a) What is "fast"? If I populate a standard TStringGrid with 100.000
rows x 100 columns (= 10 millions of cells) it takes about 9 seconds on
my PC - if BeginUpdate/EndUpdate is used. Not too bad in my eyes. If
it's too long you should use a TDrawGrid and paint the cells in the
OnDrawCell event. Since this draws only the visible cells it will occur
within the blink of an eye. Editing a TDrawGrid is a bit more
complicated, though, but doable.
(b) Multiselection has been added to the LCL grids (StringGrid and
DrawGrid) some time ago. Set option goRangeSelect, and - if the cells
selected are not contiguous - change RangeSelectMode to rsmMulti. Then
you can select individual cells by Ctrl- and Shift-Clicks like you know
from Excel.
Of course you should ask yourself the question: Is a grid with millions
of cells really something a user wants to work with?
--
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