Hi Alex,

It works!  Thanks a lot!
By thwe way, If I want to do it in MVVM way,  how to bind  RecordExpanding to a property in the ViewModel file.

Thanks!

Steve

Hello Steve,

the problem is in the handle

it should be like this:

private void expandingHandle(object sender, Infragistics.Windows.DataPresenter.Events.RecordExpandingEventArgs e)
        {

}

Thanks Alex,

but I got
Error 1 'System.Windows.RoutedEventArgs' does not contain a definition for 'Record' and no extension method 'Record' accepting a first argument of type 'System.Windows.RoutedEventArgs' could be found (are you missing a using directive or an assembly reference?) C:\download\testColorLine\testColorLine\testColorLine\Window1.xaml.cs 70 25 testColorLine

private 

void expandingHandle(object sender, RoutedEventArgs  e)
{  
   var xx = (e.Record as DataRecord).Cells[0];
}

Steve