How do I programmatically set the widths for columns on a XamDataGrid after the data source has been assigned? I need to do this from code, not xaml ...
Listen to the FieldLayoutInitialized event. You can access all the fields from the FieldLayout's Fields collection. Then set the CellWidth and LabelWidth of each field thru its Settings object, e.g.
e.FieldLayout.Fields[0].Settings.CellWidth = 75;
e.FieldLayout.Fields[0].Settings.LabelWidth = 75;