'Databinding complete' event for Silverlight 4.0 DataGrid?

I have a DataGrid that I have bound to a property:

<cd:Data开发者_Go百科Grid 
    Name="myDataGrid"
    ItemsSource="{Binding Mode=OneWay,Path=Thingies}"
    VerticalScrollBarVisibility="Auto" 
    HorizontalScrollBarVisibility="Auto">
...

When the Thingies property changes, once all rows in the DataGrid have been populated with the new contents of Thingies, I want the DataGrid to scroll to the bottom row.

In WinForms, I would have done this by subscribing to the DataBindingComplete event. MSDN Forums contains several suggestions on how to do this with Silverlight 4.0 but they range from completely evil to just plain fugly:

• start a 100ms timer on load, and scroll when it elapses
• count rows as they're added, and scroll to the bottom when the number of added rows equals the number of entities in the data source

Is there an idiomatic, elegant way of doing what I want in Silverlight 4.0?

I stumbled upon this while searching for a resolution to the same problem. I was finding that when I attempted to scroll the selected item into view after filter and sort changes that I frequently received a run time error (index out of bounds). I knew instinctively that this was because the grid was not populated at that particular moment.

Aaron's suggestion worked for me. When the grid is defined, I add an event listener:

_TheGrid.LayoutUpdated += (sender, args) => TheGrid.ScrollIntoView(TheGrid.SelectedItem, TheGrid.CurrentColumn);

This solved my problem, and seems to silently exit when the parameters are null, too.

Why not derive from DataGrid and simply create your own ItemsSourceChanged event?

       public class DataGridExtended : DataGrid
       {
            public delegate void ItemsSourceChangedHandler(object sender, EventArgs e);

            public event ItemsSourceChangedHandler ItemSourceChanged;

            public new System.Collections.IEnumerable ItemsSource
            {
                get { return base.ItemsSource; }
               set
               {
                   base.ItemsSource = value; 

                   EventArgs e = new EventArgs();
                   OnItemsSourceChanged(e);
               }
           }

           protected virtual void OnItemsSourceChanged(EventArgs e)
           {
               if (ItemSourceChanged != null)
                   ItemSourceChanged(this, e);
           }
       }

Use the ScrollIntoView method for achieving this.

myDataGrid.ItemSource = Thingies;
myDataGrid.UpdateLayout();
myDataGrid.ScrollIntoView(MyObservableCollection[MyObservableCollection.Count - 1], myDataGrid.Columns[1]);

You don't need to have any special event for this.

I think the nice way to do it, in xaml, is to have the binding NotifyOnTargetUpdated=true, and then you can hook the TargetUpdated to any event of your choice.

<ThisControl BindedProperty="{Binding xxx, NotifyOnTargetUpdated=true}"
             TargetUpdated="BindingEndedHandler">