I have such query:
var result = from tsr in db.tsr
where tsr.SomeId = x
where tsr.Sequence > ((from tsr2 in db.tsr where tsr2.SomeId = y where tsr2.FitId = tsr.FitId select tsr2.Sequence)).FirstOrDefault()
select new MyClass()
{
Properties = tsr.properties // (simplicified)
}
I wonder how to select tsr2.Sequence value into my NewClass object?
select new MyClass(){
MyClass.Property1 = tsr.Sequence.PropertyX,
MyClass.Property2 = tsr.Sequence.PropertyY,
MyClass.Property3 = tsr.Sequence.PropertyZ,
......
}
you can select and assign properties one by one. And be sure to your MyClass object properties is public
Related
what is the correct syntax to write the second list? bookid and other fields are not recognizing
var bookssublist = from bookdetails in bookslist
join bookcategories in _context.BookCategories
on bookdetails.BookId equals bookcategories.BookId
where bookcategories.CategoryId==CategoryId
select new BookBasicInfo {
count = bookcount,
BookInfo = new List<BookInfo>()
{
BookId = bookdetails.BookId,
BookTitle = bookdetails.Title,
Images = bookdetails.ThumbnailImagePath,
PublishDate = bookdetails.PublishedDate,
AuthorList = bookdetails.BookAuthors.Select(q => q.Author.Author1).ToList(),
CategoryList =bookdetails.BookCategories.Select(q=>q.Category.CategoryName).ToList(),
}
};
You are using collection initializer in a wrong way. Actually, you forgot to pass an object of type BookInfo to the initializer.
BookInfo = new List<BookInfo>()
{
new BookInfo()
{
BookId = bookdetails.BookId,
BookTitle = bookdetails.Title,
Images = bookdetails.ThumbnailImagePath,
PublishDate = bookdetails.PublishedDate,
AuthorList = bookdetails.BookAuthors.Select(q => q.Author.Author1).ToList(),
CategoryList =bookdetails.BookCategories.Select(q=>q.Category.CategoryName).ToList()
}
}
I am trying to get a record from database using linq but it keep return no record
it is very basic sql statment
select * where productid ='12553'
however the following code does not return any result. Please advise. thx you
private static IEnumerable<ProductModel> GetAllProduct(string productId)
{
using (var dc = new TestEntities())
{
var result = (from a in dc.Products
where a.productid == productId
select new ProductModel
{
ProductId = a.productid,
Name = a.ProductName
});
return result.Distinct().ToList();
}
}
You don't need projection here:
using (var dc = new TestEntities())
{
var result = from a in dc.Products
where a.productid == productId
select a;
return result.Distinct().ToList();
}
I try make table where i keep children-parent data. Ofc root of parents is "0" and here in table can by many roots. When i try make this work i got error.
Unable to create a constant value of type 'Projekty03.ViewsModels.ParagrafViewModel'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.
public ViewResult Index()
{
List<ParagrafViewModel> _paragrafparent = new List<ParagrafViewModel>();
_paragrafparent.Add(new ParagrafViewModel { ParagrafID = 0, ParagrafNazwa = "Root" });
var _paragrafparent2 = from pr in paragrafRepository.All
orderby pr.ParagrafID
select new ParagrafViewModel
{
ParagrafID = pr.ParagrafID,
ParagrafNazwa = pr.ParagrafNazwa
};
var _paragrafparent3 = _paragrafparent.Concat(_paragrafparent2).AsEnumerable();
var paragraf = from par in paragrafRepository.All
join rodzic_p in _paragrafparent3
on par.ParagrafParent equals rodzic_p.ParagrafID
orderby par.ParagrafParent, par.ParagrafID
select new ParagrafViewModel
{
ParagrafID = par.ParagrafID,
ParagrafNazwa = par.ParagrafNazwa,
ParagrafParent = par.ParagrafParent,
ParagrafCzynny = par.ParagrafCzynny,
ParagrafWplyw = par.ParagrafWplyw,
ParagrafParentNazwa = rodzic_p.ParagrafNazwa
};
return View(paragraf);
}
I believe is sht wrong with my poor magic LINQ think. How resolve this ?
Ok here is a answer for my own question. Im sure is not a pretty solution but ...
public ViewResult Index()
{
List<ParagrafViewModel> _paragrafparent = new List<ParagrafViewModel>();
_paragrafparent.Add(new ParagrafViewModel { ParagrafID = 0, ParagrafNazwa = "Root", ParagrafCzynny=false, });
var _paragrafparent2 = from pr in paragrafRepository.AllIncluding(paragraf => paragraf.WniosekPodzial)
orderby pr.ParagrafID
select new ParagrafViewModel
{
ParagrafID = pr.ParagrafID,
ParagrafNazwa = pr.ParagrafNazwa,
ParagrafParent = pr.ParagrafParent,
ParagrafCzynny = pr.ParagrafCzynny,
ParagrafWplyw = pr.ParagrafWplyw,
WniosekPodzialNazwa = pr.WniosekPodzial.WniosekPodzialNazwa
};
var _paragrafparent3 = _paragrafparent.Concat(_paragrafparent2).AsEnumerable();
var paragrafModel = from par in _paragrafparent3
join rodzic_p in _paragrafparent3
on par.ParagrafParent equals rodzic_p.ParagrafID
orderby par.ParagrafParent, par.ParagrafID
select new ParagrafViewModel
{
ParagrafID = par.ParagrafID,
ParagrafNazwa = par.ParagrafNazwa,
ParagrafParent = par.ParagrafParent,
ParagrafCzynny = par.ParagrafCzynny,
ParagrafWplyw = par.ParagrafWplyw,
ParagrafParentNazwa = rodzic_p.ParagrafNazwa,
WniosekPodzialNazwa = par.WniosekPodzialNazwa
};
return View(paragrafModel);
}
I have a stored procedure as
pr___GetArchiveData
Select * from TABLE1
SELECT * FROM TABLE2
SELECT * FROM TABLE 3
I want to get this result set into a dataset. Or access the values of three select queries!!
I have a DBML file in which when i drag and drop the stored procedure generates a code as follows:-
global::System.Data.Linq.Mapping.FunctionAttribute(Name="dbo.pr___GetArchiveData")]
public ISingleResult<pr___GetArchiveDataResult> pr___GetArchiveData([global::System.Data.Linq.Mapping.ParameterAttribute(DbType="UniqueIdentifier")] System.Nullable<System.Guid> projectID)
{
IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), projectID);
return ((ISingleResult<pr__Project_pr___GetArchiveData>)(result.ReturnValue));
}
In the code MVC3 Architecture + LINQ i have written a code to get the result set as follows :-
using (HBDataContext hb = new HBDataContext())
{
System.Data.DataSet ds = new System.Data.DataSet();
String connString = connString;
var conn = new System.Data.SqlClient.SqlConnection(connString);
var cmd = conn.CreateCommand();
cmd.CommandType = System.Data.CommandType.StoredProcedure;
cmd.CommandText = "pr__GetArchiveData";
cmd.Connection.Open();
var mReader = cmd.ExecuteReader(System.Data.CommandBehavior.SequentialAccess);
//var reader = cmd.ExecuteReader();
//using (System.Data.SqlClient.SqlDataReader mReader = cmd.ExecuteReader())
//{
// while (mReader.Read())
//{
// mReader.Read();
var tbl1 = hb.Translate<tbl1 >(mReader).ToList();
// mReader = cmd.ExecuteReader();
mReader.NextResult();
var tbl2 = hb.Translate<tbl2 >(mReader).ToList();
mReader.NextResult();
var tbl3 = hb.Translate<tbl3>(mReader).ToList();
// }
// }
}
But while running it throws error as -
"Invalid attempt to call NextResult when reader is closed."
I am not sure where i am wrong!!
I have tried using it as while
(mReader.Read())
Kindly suggest!!!!
The code gen for ISingleResult won't provide multiple result sets
Try adding your own IMultipleResults wrapper - see the tutorial in http://blogs.msdn.com/b/dditweb/archive/2008/05/06/linq-to-sql-and-multiple-result-sets-in-stored-procedures.aspx
In .dbml file for the stored procedure the code will be like
[global::System.Data.Linq.Mapping.FunctionAttribute(Name="dbo.pr__Home_GetArchiveData")]
public ISingleResult<pr__Home_GetArchiveData> pr__Home_GetArchiveData([global::System.Data.Linq.Mapping.ParameterAttribute(Name="AlbumID", DbType="UniqueIdentifier")] System.Nullable<System.Guid> albumID)
{
IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), albumID);
return ((ISingleResult<pr__Album_GetAlbumsFilesResult>)(result.ReturnValue));
}
Replace it with IMultipleResult as below `
[global::System.Data.Linq.Mapping.FunctionAttribute(Name = "dbo.pr__Home_GetArchiveData")]
[ResultType(typeof(tbl1))]
[ResultType(typeof(tbl2))]
[ResultType(typeof(tbl3))]
[ResultType(typeof(tbl4))]
public IMultipleResults pr__Home_GetArchiveData([global::System.Data.Linq.Mapping.ParameterAttribute(Name = "HOMEID", DbType = "UniqueIdentifier")] System.Nullable hOMEID)
{
IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), hOMEID);
return ((IMultipleResults)result.ReturnValue);
}
in the code .
using (HBDataContext hb = new HBDataContext())
{
using (System.Data.Linq.IMultipleResults _results = hb.pr__Home_GetArchiveData(model.HomeID))
{
List<tbl1> _tbl1= _results.GetResult<tbl1>().ToList();
List<tbl2> _tbl2= _results.GetResult<tbl2>().ToList();
List<tbl3> _tbl3= _results.GetResult<tbl3>().ToList();
List<tbl4> _tbl4= _results.GetResult<tbl4>().ToList();}}
You will get the values of the Select queries from theStoredProcedure ...
I am having trouble to return an IEnumerable and IList, I cant do it!
I am using EF 4 with POCOs
Here's the whole method:
//public IList<Genre> GetGenresByGame(int gameId)
public IEnumerable<Genre> GetGenresByGame(int gameId)
{
using(var ctx = new XContext())
{
var results =
from t0 in ctx.GameGenres
join t1 in ctx.GenreCultureDetails on t0.GenreId equals t1.GenreId
where t0.GameId == gameId && t1.CultureId == _cultureId
select new Genre
{
GenreId = t0.GenreId,
GenreName = t1.GenreName
};
return results.ToList();
}
}
I have tried different ways that I have found on the net.. but can't make it work!
Question 2:
I saw a screencast with Julie something, saying that "You should always return an ICollection" when using EF4.
Any thoughts about that ?
BR
EDIT:
When I load the page in Debug-mode i get these errors: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection. OR The entity or complex type 'XModel.Genre' cannot be constructed in a LINQ to Entities query.
Genre must not be a L2EF type. Try this:
public IEnumerable<Genre> GetGenresByGame(int gameId)
{
using(var ctx = new XContext())
{
var resultList =
from t0 in ctx.GameGenres
join t1 in ctx.GenreCultureDetails on t0.GenreId equals t1.GenreId
where t0.GameId == gameId && t1.CultureId == _cultureId
select new { t0.GenreId, t1.GenreName };
var genres = resultList.AsEnumerable().Select(o => new Genre
{
GenreId = o.GenreId,
GenreName = o.GenreName
});
return genres.ToList();
}
}
First an foremost if Genre is in the database you should select it? If you have FKs from Genre->GenreCultureDetails let me know and I can update the below, but from the looks of it you could do it like this:
using(var ctx = new XContext())
{
var results =
from g in ctx.Genre
join gcd in ctx.GenreCultureDetails on g.GenreId equals gcd.GenreId
where g.GameId == gameId && gcd.CultureId == _cultureId
select g;
return result.ToList();
}
Alternatively continue down your path select them into an annoynmous type, and then copy them. You can use select instead of convertall if you please.
IList<Genre> returnMe = Null;
using(var ctx = new XContext())
{
var results =
from t0 in ctx.GameGenres
join t1 in ctx.GenreCultureDetails on t0.GenreId equals t1.GenreId
where t0.GameId == gameId && t1.CultureId == _cultureId
select new
{
GenreId = t0.GenreId,
GenreName = t1.GenreName
};
returnMe = results.ToList().ConvertAll(x=>new Genre(){
GenreId = x.GenreId,
GenreName = x.GenreName
}
);
}
return returnMe;