Why is setting datagrid.Items.SortDescriptions(#).Direction giving an error?
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I have a wpf datagrid that I want to sort programatically as if the user had clicked on the header. After some searching I found reference to using this:

    datagrid_selected.Items.SortDescriptions(2).Direction = ComponentModel.ListSortDirection.Ascending

Looks like it would work. Intellisense says Direction is a getter and setter, but when I try to assign it to something I get the "Expression is a value and therefor cannot be the target of an assignment" error. By nature as a setter I should be able to assign this to a value, right? Any idea what's going wrong?