Sort ObservableCollection bound to DataGrid in MVVM

Sort ObservableCollection bound to DataGrid in MVVM

I have a DataGrid that I'm binding to an ObservableCollection in my view
model and I need to be able to sort the collection when the DataGrid is
sorted to so I can use this sorted order elsewhere. I'm currently using a
wrapper on the ObvservableCollection to support sorting. When the DataGrid
is sorted it only sorts the displayed data and not the underlying data in
the collection. The data consists of one integer column and one string
column and needs to support ascending and descending sort on both. I also
want to maintain the same usage as the standard DataGrid sort where you
click a column header and it toggles between ascending and descending
sort. I'm relatively new to WPF so I don't know all the ins and outs of
data and command binding, but I would think there would be a way to
accomplish what I want to do. Here is a sample xaml to illustrate my view
set up.
<DataGrid ItemsSource="{Binding mySource}"
Name="myDataGrid"
CanUserResizeRows="False"
VirtualizingStackPanel.IsVirtualizing="True"
VirtualizingStackPanel.VirtualizationMode="Recycling"
AutoGenerateColumns="False"
HeadersVisibility="Column" >
<DataGrid.Columns>
<DataGridTemplateColumn Header="Header 1"
CanUserSort="True"
SortMemberPath="firstValue">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding firstValue}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn Header="Header 2"
Width="*"
CanUserSort="True"
SortMemberPath="secondValue">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding secondValue}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
The source data is of a type something like:
public class myType
{
public int firstValue { get; set; }
public string secondValue { get; set; }
// some functions and variables...
}
Now, like I said above, I need access to the items in the collection in
their sorted order, but it does not need to specifically be an
ObservableCollection. As long as I can iterate through the items in the
collection in whatever the current order is when I access them, all is
good. I was thinking maybe a ListCollectionView or something. I also don't
want the collection to re-sort itself when new items are added to the
collection. Any new items should just be added to the end of the
collection as would normally happen.
Any ideas?