Here are two ways you can do it. The first uses the DataView associated with the datasource. It is more flexible in that you can control the sort order and sort multiple columns since you are directly setting the DataView.Sort property. The second method using the grid.Binder.Sort call to do the sort.
//Using the DataView.Sort
CurrencyManager cm = grid.BindingContext[grid.DataSource, grid.DataMember] as CurrencyManager;
if(cm != null)
{
DataView dv = cm.List as DataView;
if(dv != null)
{
dv.Sort = "someColName desc";
}
}
//using the grid.Binder.Sort
int colIndex = grid.Binder.NameToColIndex("someColName");
int field = grid.Binder.ColIndexToField(colIndex);
grid.Binder.Sort(field);