I have a list having columns like ID, Name, Country, State
The order statement needs to be in following way
.ToList().OrderByDescending(first=>t.Country).ThenBy(**if state=='GA' then ID else Name**)
My question is how to do this ThenBy clause based on some other column condition?
So it's correct that you don't want to order in the database but in memory? Even then you should not use ToList before you start ordering but AsEnumerable and add ToList at the end.
var resultList = yourQuery.AsEnumerable() // Linq-To-Objects as desired
.OrderByDescending(x => x.Country)
.ThenBy(x => x.state == "GA" ? x.ID.ToString() : x.Name)
.ToList();
Related
I would like to create a simple linq query, but I don't really know, how it should be. I have searched the net, but found nothing, what I can use or I don't know yet, that I could use it.
So, basically, I have a table with this fields: reference, vat_code, amount, vat_amount, supplier.
Now, I would like to query the records, where reference<>'' and the reference is more than once in the table. But I need all the occupians.
F.e. from
1;VF;100;27;345
2;VF;200;54;123
2;VF;-200;-54;123
2;VF;200;54;123
3;VF;300;81;888
to
2;VF;200;54;123
2;VF;-200,-54;123
2;VF;200;54;123
How would be look the linq query to this?
Thanks.
If rows with same reference should go together in results, then you should filter out rows with reference equal to empty string, then group all rows by reference and select only those groups which have more than one row.
C# sample with DataTable:
var result = dt.AsEnumerable()
.Where(r => r.Field<string>("reference") != "")
.GroupBy(r => r.Field<string>("reference"))
.Where(g => g.Count() > 1)
.SelectMany(g => g); // flatten group to sequence of rows
I have a list of record that I picked up through the code:
var list= NhSession.QueryOver<Data.Models.MembModel>()
.Where(w => w.Comp.Id == idcomp)
.JoinQueryOver(jq => jq.Ver)
.Select(s => s.Ver)
.List<Dados.Models.VerModel>();
With this code I get a list of VerModel that I have relation in a MembModel. The problem is that I what get the list of VerModel that don't be in relation in a MembModal, I think to describe this, I want to select one list that is "notin" a first list. How can I do this?
Tks
What we need, as you said, is a NOT IN (subquery) statement. And NHibernate does have a clear way how to achieve that. First the subquery, which will return MembModel collection (filtered or not - as needed), represented by the VerModel.ID
var subquery = QueryOver.Of<Data.Models.MembModel>()
// we can still filter this sub-select ... or not
// .Where(w => w.Comp.Id == idcomp)
// what we need to be returned is the reference id, the VerModel.ID
.Select(m => m.Ver.ID);
And now we will query the VerModel itself, with the NOT IN (subquery) clause:
var list = session.QueryOver<Dados.Models.VerModel>()
.WithSubquery
.WhereProperty(v => v.ID) // the ID to match the prev selected one
.NotIn(subquery) // should NOT be IN
.List<Dados.Models.VerModel>();
Check:
16.8. Subqueries
I'm trying to add a column to the following LINQ expression. I want the column to contain a string concatenation of a text value in a many table called WasteItems. The join would be on "Waste.WasteId = WasteItem.WasteId". My problem is I need to display in a single dynamic column a string such as "EW (5); EX (3)" if there was 8 records in WasteItem and the column containing the 2 character string was called WasteItem.EWC. Hope that makes sense, there must be an efficient way since I realise LINQ is very powerfull. I'm new to it and not sure how to start or go about this:
return from waste in this._db.Wastes
where (from u in _db.UsersToSites.Where(p => p.UserId == userId && p.SystemTypeId == SystemType.W)
select u.SiteId)
.Contains(waste.SiteId)
orderby waste.Entered descending select waste;
THANKS IN ADVANCE
Something like this should do:
wastes.GroupJoin(db.WasteItems, w => w.WastId, wi => wi.WasteId, (w,wi) => new { w, wi })
.AsEnumerable()
.Select(x => new
{
x.w.Name,
Items = string.Join(", ", x.wi.GroupBy(wi => wi.EWC).Select(g => string.Format("{0} ({1})", g.Key, g.Count())))
})
Where wastes is the result from your query. The AsEnumerable() is necessary because Entity Framework can not handle string.Join, so that part must be dealt with in memory.
I could not check the syntax, obviously, but at least it may show you the way to go.
how can I do multiple sort in
return (from p in _db.Pages where p.int_PostStatusId == 2 select p).OrderByDescending(m => m.int_SortOrder);
i want to do order by by int_PageId as well? first by int_SortOrder then by int_PageId
Use either ThenBy or ThenByDescending to order the result of an OrderBy or OrderByDescending:
return (...)
.OrderByDescending(m => m.int_SortOrder)
.ThenBy(m => m.int_PageId);
Or using the query syntax:
orderby p.int_SortOrder descending, p.int_PageId
A few days ago I asked a question about returning select fields from a LINQ query. Now, I want to add some grouping to the results and things are not working out.
The following query returns the correct rows but I want to limit the fields returned. For example, I only want to see the Id and Name fields.
var contactsFromDealers = Contacts.Where(x => x.ContactTypeID == 2).GroupBy (x => x.OrganizationName)
and appending .Select (x => x.Id, x.OrganizationName) doesn't help.
Any suggestions? Thanks!
you need the select before the group by i believe.
try .Select( x => new { x.Name } )