Not able to programatically select a row

[Arpit]

Hi,

here is the XAML of my radGridView

<telerikGridView:RadGridView Name="grdScope"  ScrollMode="RealTime"   DockPanel.Dock="Bottom" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" CanUserInsertRows="False"  AutoGenerateColumns="False" CanUserSortColumns="False" CanUserFreezeColumns="False" CanUserReorderColumns="False" IsFilteringAllowed="False" CanUserResizeColumns="True" Telerik:StyleManager.Theme="Office_Blue" RowStyle="{StaticResource GridViewRowStyleRow}" ScrollViewer.VerticalScrollBarVisibility="Auto" SelectionMode="Single" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ItemsSource="{Binding}" RowDetailsVisibilityMode="Collapsed" RowIndicatorVisibility="Collapsed" IsReadOnly="True" ShowGroupPanel="False"  AutoExpandGroups="True" RowLoaded="grdScope_RowLoaded" SelectionUnit="FullRow" SelectionChanged="grdScope_SelectionChanged"
 MouseDoubleClick="grdScope_MouseDoubleClick" DataLoadMode="Asynchronous" EnableColumnVirtualization="True" EnableRowVirtualization="False">

I am trying to set selected row programatically like this-

var item = ((IList<Task>) this.grdScope.ItemsSource)[this.SelectedTaskIndex];
this.grdScope.SelectedItem = item;


even when variable item has a non-null value, radGridView's SelectedItem property never changes from null to anything else when this code runs.
Am I doing something wrong?