public static IEnumerable <GraphData> GroupBy(this IQueryable <GraphData> graphData, int interval = 0, DateTime?firstDay = null)
{
if (interval <= 0)
{
return(graphData);
}
DateTime realFirstDay = firstDay ?? graphData.First().Timestamp;
var q = from d in graphData
let groupNumber = VinesenseContext.DateDiff(d.Timestamp, firstDay).Value / interval
let groupNumberInteger = DbFunctions.Truncate((double)groupNumber, 0)
group d by(int) groupNumberInteger.Value into g
select new
{
GroupNumber = g.Key,
Value = g.Average((d) => d.Value)
};
return(from v in q.AsEnumerable()
select new GraphData
{
Timestamp = realFirstDay + TimeSpan.FromDays(interval * v.GroupNumber),
Value = v.Value
});
}
public DbContext CreateContext()
{
var context = new VinesenseContext();
// context.Database.Log = (log) => Debug.WriteLine(log);
return(context);
}