Is there a way to get a list of members from a function that can be passed in to SelectList()?
So instead of doing this
var dtos = repository.QueryOver<MicrofilmExportProcessed>()
.SelectList(list => list
.Select(x => x.Member1).WithAlias(() => dto.Member1)
.Select(x => x.Member2).WithAlias(() => dto.Member2)
.Select(x => x.Member3).WithAlias(() => dto.Member3))
.List<MicrofilmExportProcessed>();
Doing something like this:
var dtos = repository.QueryOver<MicrofilmExportProcessed>()
.SelectList(getMembersFromFunc())
.List<MicrofilmExportProcessed>();
I tried creating method that returns the same type as the input parameter of the SelectList but it still tells me the input type is invalid. Not sure what I'm missing.
Something like
Func<QueryOverProjectionBuilder<InvoiceDto>, QueryOverProjectionBuilder<InvoiceDto>> GetList()
{
InvoiceDto dto = null;
return list => list.Select(w => w.Client).WithAlias(() => dto.Client);
}
and call it like
return Session.QueryOver<InvoiceDto>()
.SelectList(GetList())
.TransformUsing(Transformers.AliasToBean<InvoiceDto>())
.List<InvoiceDto>();
Related
I have multiple queries against one table. As not all columns/properties are needed I specify the columns with the help of select list. Take the following method as example. This method is working
public IEnumerable<ResultDto> GetEntityAsDto(eStatusBinderProduktion fromState, eStatusBinderProduktion toState)
{
EntityClass entityAlias = null;
ResultDto resultAlias = null;
var query = Session.QueryOver<EntityClass>(() => entityAlias)
.Where(() => entityAlias.ProduktionStatus >= (byte)fromState)
.And(() => entityAlias.ProduktionStatus <= (byte)toState);
query.SelectList(list => list
.Select(() => entityAlias.PrimaryID).WithAlias(() => resultAlias.PrimaryID)
.Select(() => entityAlias.SecondaryID).WithAlias(() => resultAlias.SecondaryID)
);
return query.TransformUsing(Transformers.AliasToBean<ResultDto>())
.List<ResultDto>();
}
As I need to define the SelectList in multiple methods, I tried to to move the SelectList into a separate method.
The following code is not working, NHibernate throws the exception
NHibernate.QueryException: 'could not resolve property: entity.PrimaryID of: MyProjectNamespace.DAL.Interfaces.Entities.EntityClass'
"
public IEnumerable<ResultDto> GetEntityAsDto(eStatusBinderProduktion fromState, eStatusBinderProduktion toState)
{
EntityClass entityAlias = null;
ResultDto resultAlias = null;
var query = Session.QueryOver<EntityClass>(() => entityAlias)
.Where(() => entityAlias.ProduktionStatus >= (byte)fromState)
.And(() => entityAlias.ProduktionStatus <= (byte)toState);
MapPropertiesOfEntityToResult(entityAlias, resultAlias, query);
return query.TransformUsing(Transformers.AliasToBean<ResultDto>())
.List<ResultDto>();
}
private void MapPropertiesOfEntityToResult(EntityClass entity, ResultDto resultAlias, IQueryOver<EntityClass, EntityClass> query)
{
query.SelectList(list => list
.Select(() => entity.PrimaryID).WithAlias(() => resultAlias.PrimaryID)
.Select(() => entity.SecondaryID).WithAlias(() => resultAlias.SecondaryID)
);
}
Additional information:
- The mappings are correct
- table is filled with test data
We do not need alias for filling SelectList. We can profit from the Type parameters coming with IQueryOver<TRoot,TSubType>:
//private void MapPropertiesOfEntityToResult(EntityClass entity
// , ResultDto resultAlias, IQueryOver<EntityClass, EntityClass> query)
private void MapPropertiesOfEntityToResult( // no need for entity
ResultDto resultAlias, IQueryOver<EntityClass, EntityClass> query)
{
query.SelectList(list => list
//.Select(() => entity.PrimaryID).WithAlias(() => resultAlias.PrimaryID)
//.Select(() => entity.SecondaryID).WithAlias(() => resultAlias.SecondaryID)
.Select(entity => entity.PrimaryID).WithAlias(() => resultAlias.PrimaryID)
.Select(entity => entity.SecondaryID).WithAlias(() => resultAlias.SecondaryID)
);
}
The entity is now a parameter of the passed Function and its type is coming from IQueryOver definition
I have a filtered list which returns all the distinctIds from MenuTable
var _parentList = _employee.Designation.Role.MenuRoles
.Select(x => new
{
MenuParentID = x.Menu.ParentID
})
.DistinctBy(x => x.MenuParentID)
.OrderBy(x => x.MenuParentID)
.ToList();
I want to select all the items from menutable which is in _parentList
This is what i have tried and an error is coming on _parentList.Contains(x.Id) which says Best overloaded match for System.Generic.contains has some invalid arguments.
MenuParentList = _db.Menus.Where(x => _parentList.Contains(x.Id))
.Select(x => new SMS.Models.ViewModel.DashboardVM.MenuParent
{
MenuParentID = x.Id,
MenuParentName = x.MenuName
})
.ToList()
Any help will be appreciated
Cf. this code:
.Select(x => new
{
MenuParentID = x.Menu.ParentID
})
This results in a list of anonymous objects with one property called MenuParentID, instead of a list of integers. The compiler creates a type for you that structurally looks like this (note that the compiler generates a non-usable class name behind the scenes instead of AnonymousType1, but you get the idea):
class AnonymousType1
{
public int MenuParentID {get;set;}
}
And _parentList would be of type List<AnonymousType1>.
Adjust your code as follows:
var _parentList = _employee.Designation.Role.MenuRoles
.Select(x => x.Menu.ParentID)
.Distinct()
.OrderBy(id => id)
.ToList();
Now _parentList is of type List<int>.
You can read more about the concept of anonymous types on msdn: https://msdn.microsoft.com/en-us/library/bb397696.aspx
In the following function I get an error when I try to return a value saying:
Cannot convert
System.Linq.IQueryable<System.Collections.Generic.IEnumerable<string>>
to return type System.Collections.Generic.IEnumerable<string>
public IEnumerable<string> GetModuleKindPropertyNames(long moduleKindId)
{
var configurationId = GetModuleKindPertypeConfigurationId(moduleKindId);
var propertyNames = _dbSis.ModuleKinds
.Where(t => t.PerTypeConfigurationId == configurationId)
.Select(x => x.PerTypeConfiguration.Properties
.Select(z => z.Name));
return propertyNames; //red line below property names
}
How can I solve this issue?
It looks like you want to select items from a collection within a collection and flatten the result into a single sequence.
Conceptually, something like:
If that's the case, you're looking for the SelectMany method:
var propertyNames = _dbSis.ModuleKinds
.Where(t => t.PerTypeConfigurationId == configurationId)
.SelectMany(x => x.PerTypeConfiguration.Properties)
.Select(z => z.Name);
I'm trying to understand how this may work.
What I would have is to have all Trees from a given list of IDs that has not rotten apples.
Looks easy but I'm fresh of NHibernate, not so good in SQL and as you can see I'm stuck.
I wrote this code down here:
Tree treeitem = null;
QueryOver<Apple> qapple = QueryOver.Of<Apple>()
.Where(x => (!x.IsRotten))
.And(Restrictions.IdEq(Projections.Property<Tree>(y => y.Id)))
// Or this one...
//.And(Restrictions.EqProperty(
// Projections.Property<Apple>(y => y.Tree.Id),
// Projections.Property<Tree>(y => y.Id)))
.Select(x => x.Id);
return this.NHibernateSession.QueryOver<Tree>()
.Where(x => x.Id.IsIn(ListOfTreeId))
.WithSubquery.WhereExists<Apple>(qapple)
.SelectList(list => list
.Select(z => z.Id).WithAlias(() => treeitem.Id)
.Select(z => z.Name).WithAlias(() => treeitem.Name)
.Select(z => z.Type).WithAlias(() => critem.Type)
.TransformUsing(Transformers.AliasToBean<Tree>())
.List<T>();
And the pseudo SQL I get is something like this:
SELECT id, name, type FROM trees WHERE id IN (1, 2, 3)
AND EXIST(SELECT id FROM apples WHERE NOT rotten AND apples.idtree = apples.id)
As you can see there's a problem with the subquery that use the same table Id instead of something like that:
EXIST(SELECT id FROM apples WHERE NOT rotten AND apples.idtree = tree.id)
I'm bit lost actually. Maybe there's another way to build this up.
Any help is welcome, thanks.
Im not sure why you are using resulttransformer when the return type is the same as the query type
return NHibernateSession.QueryOver<Tree>()
.Where(t => t.Id.IsIn(ListOfTreeId))
.JoinQueryOver<Apple>(t => t.Apples)
.Where(a => !a.IsRotten)
.List();
Update: the Compiler chooses ICollection<Apple> while it really should choose Apple therefor specify the generic argument in JoinQueryOver explicitly
Update2: to get them unique
opt 1)
...
.SetResultTransformer(Transformers.DistinctRootEntity());
.List();
opt 2)
Tree treeAlias = null;
var nonRottenApples = QueryOver.Of<Apple>()
.Where(a => !a.IsRotten)
.Where(a => a.Tree.Id == treeAlias.Id)
.Select(x => x.Id); <- optional
return NHibernateSession.QueryOver(() => treeAlias)
.Where(t => t.Id.IsIn(ListOfTreeId))
.WithSubquery.WhereExists(nonRottenApples)
.List();
I have a function which returns a list of property values from a collection:
public static List<string> GetSpeakerList()
{
var Videos = QueryVideos(HttpContext.Current);
return Videos.Where(v => v.Type == "exampleType"
.SelectMany(v => v.SpeakerName)
.Distinct()
.OrderBy(s => s)
.ToList();
}
I'd like to have a generic version which will let me determine which field I'd like projected - say instead of SpeakerName I'd like to allow selecting Video.Length or Video.Type.
I understand that SelectMany takes a Func, so what's the best way to make the Func configurable to allow passing it as a parameter into this function?
Add the function as a parameter to the method.
public static List<string> GetVideosAttribute( Func<Video,string> selector )
{
var Videos = QueryVideos(HttpContext.Current);
return Videos.Where(v => v.Type == "exampleType"
.Select( selector )
.Distinct()
.OrderBy(s => s)
.ToList();
}
var speakers = GetVideosAttribute( v => v->SpeakerName );
var topics = GetVideosAttribute( v => v->Topic );