ruby-****@sourc*****
ruby-****@sourc*****
2012年 10月 15日 (月) 01:57:48 JST
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REMOTE_ADDR = 184.145.82.7
REMOTE_HOST =
URL = http://ruby-gnome2.sourceforge.jp/hiki.cgi?tut-gtk2-treev-crs
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@@ -369,7 +369,7 @@
:Optimization Note
- You should avoid excessive use of cell data function, especially when there are many rows in the model. For instance in our last program example (toggle-rndr-2.rb) above we use it on two cell renderers or columns, namely, for 'Buy' and 'Count' columns. We could improve the performance of this program if we added as the last line the following to 'fix_parents_total' method:
+ You should avoid excessive use of cell data function, especially when there are many rows in the model. For instance in our last program example (toggle-rndr-2.rb) above we use it on two cell renderers or columns, namely, for 'Buy' and 'Count' columns. (Method invocations are rather time consuming. So do not forget data cell function and its code block are invoked for each cell in all the columns for which they are defined. If we could manage to process both columns in one data cell function rather than two, that would eliminate the need for the second pass through all the rows and subsequent 'data cell function code block' invocation.) We could improve the performance of this program if we added as the last line the following to 'fix_parents_total' method:
parent[GItm::BUY_INDEX] = total == 0 ? false : true