ADG/DataGrid prevent render even from firing immediately on property

Question

Hi,
Is there any way to tell the ADG to not re-render itself immediately after a
propertyChanged even has been fired in the dataProvider?
I have quite a wide row (lots of cells) and lots of custom logic that updates
these dependent properties on each row. i.e. calculated columns. I am doing the
calculations at dataProvider level vs labelFunctions. On each "set" function of
one of my cells in the row I raise a "propertyChanged" event if the value was
changed. Tracing through what the ADG is doing I'm finding that its re-rendering
each time I raise this event even if its in the same row. Is there any way to
tell the ADG to wait a few milliseconds in case another propertyChanged event
comes in so as to render once instead of 10 times?
If there is no ADG option what is the best pattern for this assuming I want to
do this in my underlying dataprovider objects. Should I raise custom events and
fake a itemUpdated once I know there are no more changes? I don't see a clean
way to do this however since I never really know when I'm done, and using a
timer or something of this nature seems like a major hack.
-Tom
Rest of discussion from FlexCoders ...
Re: ADG/DataGrid prevent render even from firing immediately on propertyChange
You might try enableAutoUpdate and disableAutoUpdate on ICollectionView, not
sure if that has the desired affect or not.
You could also put custom events in your model objects and manually dispatch
collection events or call explicitly tell the grid when to update.
By "explicitly tell the grid when to update" do you mean manually calling
itemUpdated at the View level?. If so does the grid actually "know" to re-render
only that updated row? It seems to me that it always re-rendered all visible
cells regardless of what was changed. So passing null or a real row into
itemUpdated has the same results.
Also if I am to manully dispatch propertyChanged from my row, and I never really
know when I'm done updating all of my dependant cells is there any good way to
do this. i.e. Cell A update cell B and cell B update updates cell E, and this
can go on indefinatley. By catchign all property changed events at Row level and
using a timer of say 50ms i would almost guarantee that I wouldn't rethrow more
than a single propertyChanged event on any of the updated cells in a row. Do you
think there is a better way to do this?
Follow up finding,
Do 10 propertyChanged events from my dataProvider cause grid to refresh once or
10 times? My most recent observations show that it's just once, though for some
reason the first load invokes my labelFunction 3 times. Is there any point in
using enableAutoUpdate if grid appears to be 'smart' enough?

Answer 1

>>And what about the the most important question, how exactly is TableAssetsViewSource defined in the XAML markup and what is
its Source property set or bound to? And what about the reproducable sample...?
Here is the Markup of the TableAssetsViewSource:
<Page.Resources>
<local:RETAILISOAMDDataSet x:Key="RETAILISOAMDDataSet"/>
<CollectionViewSource x:Key="TableRegionsViewSource" Source="{Binding tableRegions, Source={StaticResource RETAILISOAMDDataSet}}"/>
<CollectionViewSource x:Key="TableLocationsViewSource" Source="{Binding tableLocations, Source={StaticResource RETAILISOAMDDataSet}}"/>
<CollectionViewSource x:Key="TableAssetsViewSource" Source="{Binding tableAssets, Source={StaticResource RETAILISOAMDDataSet}}"/>
</Page.Resources>
The ItemsSource of the DataGrid is bound to the TableAssetsViewSource:
<DataGrid DataContext="{StaticResource TableAssetsViewSource}" ItemsSource="{Binding}" x:Name="TableAssetsDataGrid" AutoGenerateColumns="False" EnableRowVirtualization="True" Margin="15,10,10,10" RowDetailsVisibilityMode="VisibleWhenSelected" Grid.Column="1" HeadersVisibility="Column" CanUserResizeRows="False" IsReadOnly="True">
Just remember, this code was auto-generated with the drag & drop onto the Page, so I did little in terms of setting the actual bindings.
All in all, what I have done so far works as intended, except that when I want to add a row to the table it does not reflect, and that it only shows after refreshing/restarting the application.
I will try and put together a reproducable sample.