ruby-****@sourc*****
ruby-****@sourc*****
2012年 10月 8日 (月) 04:52:06 JST
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REMOTE_ADDR = 184.145.80.187
REMOTE_HOST =
URL = http://ruby-gnome2.sourceforge.jp/hiki.cgi?tut-gtk2-treev-crs
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@@ -170,7 +170,7 @@
-Sometimes when certain cell value is changed by the user it may effect one or more other cells on the tree view indicating data related dependencies in tree view. In our 'Grocery List' example such dependencies can be found. Remember that in any product category row the column 'Count' displays the number of individual items from that category for which their respective 'Buy' columns are checked, i.e. in their model columns they contain Boolean value TRUE.
+Sometimes when certain cell value is changed by the user it may effect one or more other cells on the display indicating data related dependencies in tree view. In our 'Grocery List' example such dependencies can be found. Remember that in any product category row the column 'Count' displays the number of individual items from that category for which their respective 'Buy' columns are checked, i.e. in their model columns they contain Boolean value TRUE.
For instance, lets consider the initial state of the 'Grocery List' display immediately after you start up the program, in which the row identified by product 'Paper Towels' originally had the 'Buy' column checked (TRUE), and in the 'Count' column value 1. At the same time the pertinent product category row (Cleaning Supplies), due to the 'Toilet Paper' row which is also checked and has value 3 in its 'Count' column, contains value 4 in its 'Count' column, and indeed the 'Buy' column checked. Should a user then toggle the 'Buy' column for 'Paper Towels' row to unchecked (FALSE), that would ultimately affect the pertinent product category's 'Count' value to display now decreased value 3. If however, the user also unchecks the 'Toilet Paper' row, we will witness two changes in the 'Cleaning Supplies' product category row, namely, its 'Count' value will become 0 (zero), and the 'Buy' column will become unchecked. This reveals two data dependencies in our tree view. But there is
a third issue lurking behind these dependencies here, namely it should not be possible for a user to manually toggle the check button for any product category.