Did you try the same scenario with the Spark DataGrid? More performance work has been done on that since it was suppose to replace mx:AdvancedDataGrid.
Carol On 3/6/12 10 :32PM, "Justin Mclean" <jus...@classsoftware.com> wrote: >Hi, > >Is a bit quiet around here so I thought I bring up something odd I found >a while ago. > >If you run the sample found here on the whiteboard: > >http://svn.apache.org/viewvc/incubator/flex/whiteboard/jmclean/datagrid/sr >c/TooMuchValidation.mxml > >and move the mouse about you'll see how many times validiateNow is being >called for each cell. > >If you move sideways cell to cell you sell that each cell is the row is >validated twice and the first cell 4 times > >If you move up or down a row you'll see that each cell in both rows are >validated and the first cells twice. > >Obviously this could be optimised. With large datagrids (and custom item >renderers) this slows down things a little. > >So a few questions: > >Why is the first cell in each row being validated more than once? (I've >not worked this out so far). > >One of the validateNow is being called from drawItem in AdvancedList Base >(line 4800 or so) like so: > > if (item is IFlexDisplayObject) > { > if (item is IInvalidating) > { > IInvalidating(item).invalidateDisplayList(); > IInvalidating(item).validateNow(); > } > } > > >Do we need to call invalidateDisplayList as validateNow would also call >updateDisplayList right? As no properties are changed on the item (as far >as I can tell) I'm not even sure we need to call validateNow at all >perhaps just invalidateDisplayList is enough? Does drawItem need to >called at all for the entire row if moving mouse over cell left or right? > >Hopefully someone else has encountered into this issue and/or can cast >some more light on it. > >This is not as far as I know an existing issue reported in the Adobe bug >base. > >Thanks, >Justin
