I need to translate the following LINQ query to Dynamic LINQ that accepts several grouping columns based on user input. Basically I have a bunch of dropdownlists that apply groupings and I don't want to enumerate every combination of groupings. If Dynamic LINQ fails, I may have to construct a SQL query manually, and nobody wants that.
var grouping = ( from entry in ObjectContext.OmniturePageModules
where entry.StartOfWeek >= startDate && entry.StartOfWeek <= endDate &&
( section == "Total" || section == "All" || entry.Section == section ) &&
( page == "Total" || page == "All" || entry.Page == page ) &&
( module == "Total" || module == "All" || entry.Module == module )
group entry by new
{
entry.Page, // I want to be able to tell this anonymous type
entry.Module, // which columns to group by
entry.StartOfWeek // at runtime
}
into entryGroup
select new
{
SeriesName = section + ":" + entryGroup.Key.Page + ":" + entryGroup.Key.Module,
Week = entryGroup.Key.StartOfWeek,
Clicks = entryGroup.Sum( p => p.Clicks )
} );
I have no clue how to do this as Dynamic LINQ is totally undocumented outside of the "hello world!" select/where/orderby cases. I just can't figure out the syntax.
Something like:(?)
var grouping = ObjectContext.OmniturePageModules.Where(entry => entry.StartOfWeek >= startDate && entry.StartOfWeek <= endDate &&
( section == "Total" || section == "All" || entry.Section == section ) &&
( page == "Total" || page == "All" || entry.Page == page ) &&
( module == "Total" || module == "All" || entry.Module == module ))
.GroupBy("new (StartOfWeek,Page,Module)", "it")
.Select("new (Sum(Clicks) as Clicks, SeriesName = section + key.Page + Key.Module, Week = it.Key.StartOfWeek)");
I'm using the DynamicQueryable class in System.Linq.Dynamic. See: http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
Follow-up: Enigmativity's solution worked mostly. For some reason it doesn't want to group by the datetime "StartOfWeek" column -- workaround is just to do a secondary grouping:
var entries = ( from entry in ObjectContext.OmniturePageModules
where entry.StartOfWeek >= startDate
&& entry.StartOfWeek <= endDate
&& ( section == "Total" || section == "All" || entry.Section == section )
&& ( page == "Total" || page == "All" || entry.Page == page )
&& ( module == "Total" || module == "All" || entry.Module == module )
select entry ).ToArray(); // Force query execution
var grouping = from entry in entries
let grouper = new EntryGrouper( entry, section, page, module )
group entry by grouper into entryGroup
select new
{
entryGroup.Key.SeriesName,
entryGroup.Key.Date,
Clicks = entryGroup.Sum( p => p.Clicks ),
};
var grouping2 = (from groups in grouping
group groups by new {groups.SeriesName, groups.Date } into entryGroup
select new
{
entryGroup.Key.SeriesName,
entryGroup.Key.Date,
Clicks = entryGroup.Sum( p => p.Clicks ),
} );
but this seems to seriously degrade performance... =/