Building the 'where' clause in a Linq query - c#

In this query, I always want the 'normal' type element.
If the _includeX flag is set, I want the 'workspace' type elements, too.
Is there a way to write this as one query? Or build the where clause based on _includeX before submitting the query?
if (_includeX) {
query = from xElem in doc.Descendants(_xString)
let typeAttributeValue = xElem.Attribute(_typeAttributeName).Value
where typeAttributeValue == _sWorkspace ||
typeAttributeValue == _sNormal
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
}
else {
query = from xElem in doc.Descendants(_xString)
where xElem.Attribute(_typeAttributeName).Value == _sNormal
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
}

You can break it into a separate predicate:
Predicate<string> selector = x=> _includeX
? x == _sWorkspace || x == _sNormal
: x == _sNormal;
query = from xElem in doc.Descendants(_xString)
where selector(xElem.Attribute(_typeAttributeName).Value)
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
Or inline the condition:
query = from xElem in doc.Descendants(_xString)
let typeAttributeValue = xElem.Attribute(_typeAttributeName).Value
where (typeAttributeValue == _sWorkspace && _includeX) ||
typeAttributeValue == _sNormal
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
Or remove query expression usage and do it this way:-
var all = doc.Descendants(_xString);
var query = all.Where( xElem=> {
var typeAttributeValue = xElem.Attribute(_typeAttributeName).Value;
return typeAttributeValue == _sWorkspace && includeX ) || typeAttributeValue == _sNormal;
})
.Select( xElem =>
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
})
Or combine the first and third and do:
Predicate<string> selector = x=> _includeX
? x == _sWorkspace || x == _sNormal
: x == _sNormal;
query = doc.Descendants(_xString)
.Where(xElem => selector(xElem.Attribute(_typeAttributeName).Value))
.Select(xElem => new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};)
It all depends what's going to work cleanest in your context.
Do yourself a favour and buy (and read!) C# in Depth and it'll all make sense a lot more quickly that learning this stuff bit by bit...

Related

How to assign stored procedure result to a entity inside select statement in entity framework

I want to assign GetMajorMileStone(projecttask.ProjectTaskId) result to MajorMilestone.
I tried but getting following error:
LINQ to Entities does not recognize the method
'System.Data.Objects.ObjectResult1[.Poco.GetMajorMileStone_Result]
GetMajorMileStone(System.Nullable1[System.Guid])' method, and this
method cannot be translated into a store expression.'
Here is my code:
public ProjectsPayload GetProjectSchedule(int projectid, bool includeArchived, DateTime startDate, DateTime endDate, int userId)
{
using (var db = new Entities())
{
try
{
db.CommandTimeout = 1200;
var query = from project in db.Project.Where(t => (t.Active || t.TempActive) && t.ProjectId == projectid)
join UP in db.User_X_Project on project.ProjectId equals UP.ProjectId
where (UP.UserId == userId && UP.Active)
orderby (project.Priority ?? int.MaxValue)
orderby (project.ProjectTitle)
select new
{
Project = project,
ProjectTask = from projecttask in project.ProjectTask.Where(t => t.Active && (
(includeArchived == true && t.TaskStatusId == (int?)TaskStatus.Archived) ||
(includeArchived == false && t.TaskStatusId != (int?)TaskStatus.Archived))
|| t.TaskStatusId != (int?)TaskStatus.Planned)
join schedule in project.ProjectTask.SelectMany(p => p.ProjectTaskSchedule) on projecttask.ProjectTaskId equals schedule.ProjectTaskId
join daily in db.ProjectTaskSchedule.SelectMany(p => p.DailyStatus) on schedule.ProjectTaskScheduleId equals daily.ProjectTaskScheduleId
where schedule.Active && daily.Active && projecttask.Active && schedule.ResourceId == userId && (
(EntityFunctions.TruncateTime(daily.Date) >= EntityFunctions.TruncateTime(startDate.Date) &&
EntityFunctions.TruncateTime(daily.Date) <= EntityFunctions.TruncateTime(endDate.Date))
)
orderby schedule.StartDate
select new
{
ProjectTask = projecttask,
ProjectTaskSchedule = from projecttaskschedule in projecttask.ProjectTaskSchedule.Where(t => t.Active && t.ResourceId == userId)
select new
{
ProjectTaskSchedule = projecttaskschedule,
DailyStatus = projecttaskschedule.DailyStatus.Where(t => t.Active),
},
CritiCality = from cr in db.CritiCality.Where(ts => ts.ProjectTaskId == projecttask.ProjectTaskId) select cr,
MMDetails = from mm in db.MMDetails.Where(ts => ts.ProjectTaskId == projecttask.ProjectTaskId) select mm,
MajorMilestone = db.GetMajorMileStone(projecttask.ProjectTaskId).FirstOrDefault(),
}
};
var materialized = query.AsEnumerable();
var result = materialized.Select(t => new ProjectsPayload
{
ProjectId = t.Project.ProjectId,
ProjectTitle = t.Project.ProjectTitle,
Priority = t.Project.Priority,
ProjectDescription = t.Project.ProjectDescription,
ProjectTask = t.Project.ProjectTask.Select(x => new ProjectTaskPayload
{
Duration = x.Duration,
Hours = x.Hours,
IsOngoing = x.IsOngoing,
IsSummaryTask = x.IsSummaryTask,
Priority = x.Priority,
ParentTaskId = x.ParentTaskId,
ProjectId = x.ProjectId,
ProjectTaskId = x.ProjectTaskId,
TaskAcceptanceId = x.TaskAcceptanceId,
TaskStatusId = x.TaskStatusId,
TaskTitle = x.TaskTitle,
TaskTypeId = x.TaskTypeId,
IsMileStone = x.IsMileStone,
IsTimeAwayTask = x.IsTimeAwayTask,
AutoSize = x.AutoSize,
IsArchivedTasksInSummary = x.IsArchivedTasksInSummary,
IsASAP = x.IsASAP,
IsAutoCompleteEnable = x.IsAutoCompleteEnable,
IsSharedDiffSchedules = x.IsSharedDiffSchedules,
LongDescription = x.LongDescription,
OwnerId = x.OwnerId,
ShowInSummaryTask = x.ShowInSummaryTask,
SubTypeID = x.SubTypeID,
MMDetails1 = x.MMDetails1.Select(MD => new MMDetailsPayload { MajorMilestoneId = MD.MajorMilestoneId, ProjectTaskId = MD.ProjectTaskId, MMDetailsId = MD.MMDetailsId, Slack = MD.Slack }),
ProjectTaskSchedule = x.ProjectTaskSchedule.Select(a => new ProjectsTaskSchedulePayload
{
ProjectTaskScheduleId = a.ProjectTaskScheduleId,
StartDate = a.StartDate,
EndDate = a.EndDate,
ProjectTaskId = a.ProjectTaskId,
ResourceId = a.ResourceId,
ArchiveEndDate = a.ArchiveEndDate,
ArchiveStartDate = a.ArchiveStartDate,
IsSharedTask = a.IsSharedTask,
TimeUnitId = a.TimeUnitId,
DailyStatus = a.DailyStatus.Select(Ds => new DailyStatusPayload
{
Active = Ds.Active,
ActualHours = Ds.ActualHours,
DailyStatusId = Ds.DailyStatusId,
Date = Ds.Date,
ProjectTaskScheduleId = Ds.ProjectTaskScheduleId,
IsCloseOutDay = Ds.IsCloseOutDay,
Priority = Ds.Priority
})
}).ToList(),
CritiCality = x.CritiCality.Select(c => new CriticalityPayload { CriticalityId = c.CriticalityId, CriticalityTypeId = c.CriticalityTypeId, ProjectTaskId = c.ProjectTaskId }).ToList(),
}).ToList()
}).FirstOrDefault();
return result;
}
catch (EntityException ex)
{
if (ex.Message == connectionException)
throw new FaultException(dbException);
else
throw new FaultException(ex.Message);
}
}
}
My result is like this, I want all entities(Criticality,MMDetails and MajorMileStone), Not only MajorMileStone
MajorMileStone Result
I separate multiple simple query for testing. Please try to execute below two query and check whether successful or not.
// First query to get project
var query1 = from project in db.Project.Where(t => (t.Active || t.TempActive) && t.ProjectId == projectid)
join UP in db.User_X_Project on project.ProjectId equals UP.ProjectId
where (UP.UserId == userId && UP.Active)
orderby (project.Priority ?? int.MaxValue)
orderby (project.ProjectTitle)
.Select new { project = project }.ToList();
// Second query to get projecttask from query1.project and execute store procedure
var query2 = from projecttask in query1.project.ProjectTask.Where(t => t.Active && (
(includeArchived == true && t.TaskStatusId == (int?)TaskStatus.Archived) ||
(includeArchived == false && t.TaskStatusId != (int?)TaskStatus.Archived)) ||
t.TaskStatusId != (int?)TaskStatus.Planned)
join schedule in query1.project.ProjectTask.SelectMany(p => p.ProjectTaskSchedule) on projecttask.ProjectTaskId equals schedule.ProjectTaskId
join daily in db.ProjectTaskSchedule.SelectMany(p => p.DailyStatus) on schedule.ProjectTaskScheduleId equals daily.ProjectTaskScheduleId
where schedule.Active && daily.Active && projecttask.Active && schedule.ResourceId == userId && (
(EntityFunctions.TruncateTime(daily.Date) >= EntityFunctions.TruncateTime(startDate.Date) &&
EntityFunctions.TruncateTime(daily.Date) <= EntityFunctions.TruncateTime(endDate.Date))
)
orderby schedule.StartDate
.Select new
{
MajorMilestone = db.GetMajorMileStone(projecttask.ProjectTaskId).FirstOrDefault(),
}.ToList();
Let me know it has result or not. In the meantime you can check this "Method cannot be translated into a store expression"
It has link to article about what not to do with linq. Nested Linq like this is best to avoid and better to split up the query. If it affects the execution time, it better to execute raw sql.

Linq Subquery in IQueryable Select

I am having problems with subqueries in a linq-to-entities IQueryable query.
Can anybody tell me what is the correct way to do a sub query when building up an IQueryable query? Based on my full example below.
I get the following error when ToArray() is called on the query:
An exception of type 'System.NotSupportedException' occurred in System.Data.Entity.dll but was not handled in user code
Additional information: LINQ to Entities does not recognize the method 'System.Data.Entity.IDbSet`1[MyDomain.NewsWorthyPressReleases.NewsWorthyWire] Set[NewsWorthyWire]()' method,
and this method cannot be translated into a store expression.
So for example you can see one of my subqueries here:
BwIncluded = (from abw in Context.Set<NewsWorthyWire>()
where abw.WireId == PressWireIds.BUID
where abw.NewsWorthyCampaignId == nc.Id
select abw).Any(),
I am trying to populate BwIncluded with true or false if any() exists.
And the entire build up of the query is as follows, it is IMPORTANT to understand where the sub-queries are used:
private Func<EntityFramework.IDbContext, IQueryable<NewsWorthyPressRelease>> GetSearchNewsWorthyQuery(NewsWorthySearchFields searchFields)
{
return context =>
{
//domain models
var newsWorthyCampaigns = context.Set<NewsWorthyCampaign>();
var wires = context.Set<NewsWorthyWire>();
var campaigns = context.Set<Campaign>();
//predicates
var newsWorthyCampaignPredicate = PredicateBuilder.True<NewsWorthyCampaign>();
var wirePredicate = PredicateBuilder.True<NewsWorthyWire>();
var campaignPredicate = PredicateBuilder.True<Campaign>();
// build up the predicate queries
//Status was input
if (searchFields.StatusId.HasValue && searchFields.StatusId.Value > 0)
{
newsWorthyCampaignPredicate = newsWorthyCampaignPredicate.And(x => x.Id == searchFields.StatusId);
}
//Id was input
if (searchFields.Id.HasValue && searchFields.Id.Value > 0)
{
wirePredicate = wirePredicate.And(x => x.Id == searchFields.Id);
}
//Title was input
if (!string.IsNullOrEmpty(searchFields.Title))
{
wirePredicate = wirePredicate.And(x => x.Title.Contains(searchFields.Title));
}
//Wire was input
if (searchFields.PressWireId.HasValue && searchFields.PressWireId.Value > 0)
{
wirePredicate = wirePredicate.And(x => x.Id == searchFields.PressWireId);
}
//Created By was chosen
if (searchFields.CreatedById.HasValue && searchFields.CreatedById.Value > 0)
{
campaignPredicate = campaignPredicate.And(x => x.IdentityId == searchFields.CreatedById);
}
//Create Date From was chosen
if (searchFields.DateCreatedFrom.HasValue)
{
campaignPredicate = campaignPredicate.And(y => y.CreationDate >= searchFields.DateCreatedFrom);
}
//Create Date To was chosen
if (searchFields.DateCreatedTo.HasValue)
{
campaignPredicate = campaignPredicate.And(y => y.CreationDate <= searchFields.DateCreatedTo);
}
//the query
var nwprQuery = (from nc in newsWorthyCampaigns.Where(newsWorthyCampaignPredicate)
join w in wires.Where(wirePredicate)
on nc.Id equals w.NewsWorthyCampaignId
join c in campaigns.Where(campaignPredicate)
on nc.CampaignId equals c.Id
select new NewsWorthyPressRelease
{
Id = nc.Id,
Title = w.Title,
//BwIncluded = false,
//GnIncluded = false,
//PrIncluded = false,
BwIncluded = (from abw in Context.Set<NewsWorthyWire>()
where abw.WireId == PressWireIds.BUID
where abw.NewsWorthyCampaignId == nc.Id
select abw).Any(),
GnIncluded = (from agw in Context.Set<NewsWorthyWire>()
where agw.WireId == PressWireIds.GLID
where agw.NewsWorthyCampaignId == nc.Id
select agw).Any(),
PrIncluded = (from anw in Context.Set<NewsWorthyWire>()
where anw.WireId == PressWireIds.PRID
where anw.NewsWorthyCampaignId == nc.Id
select anw).Any(),
CreatedBy = c.CreatedBy.FirstName + " " + c.CreatedBy.Surname,
CreateDate = c.CreationDate,
Status = nc.NewsWorthyStatus.Name,
}).AsNoTracking();
return nwprQuery;
};
}
Can anyone help with this?
Thanks

Create a search method with AND/OR options in Linq and C#

I'm trying to create some methode for searching and filtring data in databese using c# and asp.net mvc 4 (linq)
public ActionResult Search_Names_Using_Location(string b,string d, int c=0,int Id=0)
{
ViewBag.Locations = db.Locations.ToList();
var agentlocation = new AgentLocationViewModel();
agentlocation.agents = new List<Agent>();
agentlocation.agents = (from a in db.Agents
where a.LocationId == Id
&& (a.LocationName == b)
&& (a.age > c )
select a).ToList();
return View(agentlocation);
}
The problem is that user can let some texboxes empty, so the value of Id or a or b can be null so the query will get nothing.
Is their any suggestions to do that (i can go with if else but that's hard if i have 7 or 8 strings)?
You can check for null inside query
public ActionResult Search_Names_Using_Location(string b,string d,
int c=0,int Id=0,)
{
ViewBag.Locations = db.Locations.ToList();
var agentlocation = new AgentLocationViewModel();
agentlocation.agents = new List<Agent>();
var noId = string.IsNullOrWhitespace(Id);
var noB = string.IsNullOrWhitespace(b);
agentlocation.agents = (from a in db.Agents
where (noId || a.LocationId == Id)
&& (noB || a.LocationName == b)
&& (a.age > c )
select a).ToList();
return View(agentlocation);
}
If you have AND conditions only you can use
var query = db.Agents;
if (Id != 0)
{
query = query.Where(x => x.LocationId == Id)
}
if (!string.IsNullOrWhitespace(b))
{
query = query.Where(x => x.LocationName == b)
}
...
var result = query.ToList(); // actual DB call
This will remove useless empty conditions, like WHERE (0 = 0 OR LocationId = 0)
In case of OR conditions and combinations you can take a look at PredicateBuilder
So you can use Or and And predicate combinations like this:
IQueryable<Product> SearchProducts (params string[] keywords)
{
var predicate = PredicateBuilder.False<Product>();
foreach (string keyword in keywords)
{
string temp = keyword;
predicate = predicate.Or (p => p.Description.Contains (temp));
}
return dataContext.Products.Where (predicate);
}

Select from list linq

I am trying to get matches from linq query-
public ActionResult TagFilter(TagModel tag) {
List<CardModel> cardlist = null;
var cardtaglist = (from u in db.CardTagTables
where u.CardTagName == tag.tagName
select u).ToList();
cardlist = (from u in db.CardTables
where u.CardID == cardtaglist.Where(e=>e.FKCardTagID==u.CardID)
select new CardModel {
cardHashCode = tag.tagName,
cardDate = u.CardDate,
cardFileName = u.CardFileName,
cardFilePath = u.CardFilePath,
cardID = u.CardID,
cardTitle = u.CardTitle
}).ToList();
if (cardlist.Count == 0) {
return Json(new { success = false });
}
else {
return PartialView("_FunHomePartial", cardlist);
}
}
Where match of tag=>tagName would be from list cardtaglist.
I get Cannot implicitly convert type int to bool error in line-
where u.CardID == cardtaglist.Where(e=>e.FKCardTagID==u.CardID)
How Do I match elements from list cardtaglist ?
How to about replace
u.CardID == cardtaglist.Where(e=>e.FKCardTagID==u.CardID)
with
cardtaglist.Any(e=>e.FKCardTagID==u.CardID)
First of all, why you select all CardTagTable entity, if you use only FKCardTagID!? The best way - to select only required fields:
var cardtagIds = (from u in db.CardTagTables
where u.CardTagName == tag.tagName
select u.FKCardTagID).ToList();
About your error, you are traying to compare IQueriable with numeric value. You can use Contains method in this case:
cardlist = (from u in db.CardTables.Where(u => cardtagIds.Contains(u.CardID));
select new CardModel {
....
Edit
Also, this query can be optimized:
cardlist = (from u in db.CardTables.Where(u =>
db.CardTagTables
.Where(ct => ct.CardTagName == tag.tagName)
.Select(ct => ct.FKCardTagID)
.Contains(u.CardID))
select new CardModel {
....
Use:
var result=cardtaglist.Any(e=>e.FKCardTagID==u.CardID)

how to create dynamic linq query based on search criterias

I have a search form which i want to use to search a database for data. The searchbox has 4 checkboxes and 1 textfield. The problem is how do i build the linq query considering i dont know beforehand what textboxes the user will check for filtering the search. What i have so far is:
[HttpPost]
public ActionResult search(string ulv, string bjorn, string jerv, string gaupe)
{
var query = (from o in db.observasjonene select o);
if (ulv != null)
{
query = query.Where(o => o.art == ulv);
}
if (bjorn != null)
{
query = query.Where(o => o.art == bjorn);
}
if (jerv != null)
{
query = query.Where(o => o.art == jerv);
}
if (gaupe != null)
{
query = query.Where(o => o.art == gaupe);
}
IEnumerable ls = query.ToList();
return Json(ls, JsonRequestBehavior.AllowGet);
}
The problem with the "where" clause is that if a condition is true, it overwrites the results from the earlier condition. I guess i need an "or" statement or something..
If I have understood your question correctly, you want to check if art equals to any of provided values. You can combine those values into collection and check if collection contains art value:
var values = new [] { ulv, bjorn, jerv, game }.Where(v => v != null);
var query = from o in db.observasjonene
where values.Contains(o.art)
select o;
EF translates Contains into SQL IN operator.
I'm using two approaches in this case:
Build dynamic query:
var q = DB.Invoices.AsQueryable();
if (isPresented != null)
q = q.Where(iv => iv.IsPresented == isPresented);
if (ID != null)
q = q.Where(iv => iv.ID == ID.Value);
...........................
return from iv in q
orderby iv.DueDate descending
select iv;
Use Union to combine search results:
var q1 = db.FeeInvoice.Where(fi => [QUERY1]));
if (isPresented != null)
{
var q2 = db.FeeInvoice.Where(fi =>[QUERY2]));
q1.Union(q2);
}
if (ID != null)
{
var q3 = db.FeeInvoice.Where(fi =>[QUERY3]);
q1.Union(q3);
}
...........................
You are comparing all the parameters value to single column in the query ie. art (see you have written same column name in each where condition) . I'm not sure why are you doing so? you can simply take single parameter which compare the value like this
public ActionResult search(string value)
{
query = query.Where(o => o.art == value);
}
or if it is by mistake and you want to apply where condition along with multiple column then you can try something like this
query=query.Where(o => (o.art == ulv || ulv == string.Empty) && (o => o.bjorn == bjorn || bjorn=string.empty) && (o.jerv == jerv || jerv == string.Empty) && (o.gaupe == gaupe || gaupe == string.Empty));
Note: I assume your column name as your parameters name.

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