Develop Reference

How can I set the value of a parameter in a Select using LINQ?

I am trying to create a report using LINQ but having problems.
var AppVersion = Start
.Select(x => new AppVersionModel
{
DateYYMMDD = x.DateYYMMDD,
Android043 =
})
What I would like to do is to:
set the value of Android043 to be equal to a 1 here if (x => x.IsAndroid && x.AppVersion == "0.4.3")
But I am not sure how to do that. Can someone give advice to me.

Just wrap the expression inside parentheses to be unambiguous (though the parentheses are unnecessary)
IEnumerable<AppVersionModel> appVersion = Start
.Select( x => new AppVersionModel
{
DateYYMMDD = x.DateYYMMDD,
Android043 = ( x.IsAndroid && x.AppVersion == "0.4.3" )
} );

You can try,
var AppVersion = Start
.Select(x => new AppVersionModel
{
DateYYMMDD = x.DateYYMMDD,
Android043 = (x.IsAndroid && x.AppVersion == "0.4.3") ? 1 : //someothervalue
});

How to use the Exact array value instead of Contains [duplicate]

This question already has answers here:
LINQ equal instead of Contains
(3 answers)
Closed 5 years ago.
I need to use Equals method or something similar instead of using Contains method because i want to search in database for the exact values in selectedDeviceTypeIDs array not any of it.
IEnumerable<Guid> selectedDeviceTypeIDs = DeviceTypeIDs
.Split(',')
.Select( Guid.Parse )
.AsEnumerable();
query = query
.Where( j =>
j.HospitalDepartments.Any( jj =>
jj.Units.Any( m =>
m.Devices.Any( w =>
selectedDeviceTypeIDs.Contains( w.DeviceTypeID )
)
)
)
);
Here is my full code
public HttpResponseMessage GetAvailableHospitalsByAjax(System.Guid? DirectorateOfHealthID = null, System.Guid? UnitTypeID = null, string DeviceTypeIDs = null)
{
Context db = new Context();
var query = db.Hospitals.AsQueryable();
if (DeviceTypeIDs != null)
{
IEnumerable<Guid> selectedDeviceTypeIDs = DeviceTypeIDs.Split(',').Select(Guid.Parse).AsEnumerable();
query = query.Where(j => j.HospitalDepartments.Any(jj => jj.Units.Any(m => m.Devices.Any(w => selectedDeviceTypeIDs.Contains(w.DeviceTypeID)))));
}
if (UnitTypeID != null)
{
query = query.Where(j => j.HospitalDepartments.Any(www => www.Units.Any(u => u.UnitTypeID == UnitTypeID)));
}
if (DirectorateOfHealthID != null)
{
query = query.Where(h => h.DirectorateHealthID == DirectorateOfHealthID);
}
query = query.Where(j => j.HospitalDepartments.Any(u => u.Units.Any(d => d.Devices.Any(s => s.Status == Enums.DeviceStatus.Free)))
&& j.HospitalDepartments.Any(hd => hd.Units.Any(u => u.Beds.Any(b => b.Status == Enums.BedStatus.Free))));
var list = query.ToList();
return Request.CreateResponse(HttpStatusCode.OK, list);
}

Your problem is not Contains() but with the Any() method used in your query which will return true immediately after it finds a device whose DeviceTypeID is in the provided selectedDeviceTypeIDs list.
If you need to check if all the devices of a unit match all the items in the list, you could use:
query = query
.Where(j =>
j.HospitalDepartments.Any(jj =>
jj.Units.Any(m =>
m.Devices.All(
w => selectedDeviceTypeIDs.Contains(w.DeviceTypeID))
&&
selectedDeviceTypeIDs.All(
g => m.Devices.Select(d => d.DeviceTypeID).Contains(g))
)
)
);
Note that if you have duplicate items in the selectedDeviceTypeIDs but not in the Devices of the Unit, it will still return true.

Is it possible to insert a LinqKit PredicateBuilder as a sub query?

I've currently got a working multi level predicate shown below...
var predicate = PredicateBuilder.New<Patient>();
foreach (var code in codeArray) // ect..["AB12", "W231", "Q213"]
{
string localCode = code;
predicate.Or(p => p.Requests.Any(
u => u.Records.Any(
t => t.OutgoingRecords.Any(
s => s.Code == localCode)
)
)
);
}
res = query.AsExpandable().Where(predicate);
// Query is built up from an outside source and is eventually turned into a list via .ToListAsync()
Which is fine except as far as I'm aware it is producing a query in the form of...
query = p => p.PatientEpisodes.Any(u => u.EpisodeGroupings.Any(t => t.EpisodeDiagnoses.Any(s => s.Code == 'AB12'))) ||
p.PatientEpisodes.Any(u => u.EpisodeGroupings.Any(t => t.EpisodeDiagnoses.Any(s => s.Code == 'W231'))) ||
p.PatientEpisodes.Any(u => u.EpisodeGroupings.Any(t => t.EpisodeDiagnoses.Any(s => s.Code == 'Q213')))
Which is just overkill (and somewhat wrong) when all I really should be producing is...
query = p => p.PatientEpisodes.Any(u => u.EpisodeGroupings.Any(t => t.EpisodeDiagnoses.Any(s => s.Code == 'AB12' || s.Code == 'W312' || s.Code == 'Q213')))
Is there a way to insert the predicate at a sub level of a query such as below? My current attempts to do so have failed so far.
var predicate = PredicateBuilder.New<RecordCode>();
foreach (var code in codeArray)
{
string localCode = code;
predicate.Or(p => p.Code == localCode);
}
query = query.AsExpandable().Where(
s => s.Requests.Any(
c => c.Records.Any(
d => d.OutgoingRecords.Any(predicate))));
Many thanks in advance.

How to filter a Lambda expression from possible Querystrings in C#

I'm trying to filter results via a query string but not sure of the best way to do this, what i have so far is:
var topic = Request.QueryString["topic"];
var date = Request.QueryString["date"];
var keyword = Request.QueryString["keyword"];
if (!string.IsNullOrEmpty(topic) || !string.IsNullOrEmpty(date) || !string.IsNullOrEmpty(keyword))
{
items = root.Children().Where(x => x.IsDocumentType("Event-Item") &&
x.GetPropertyValue("eventTitle").ToString().Contains(topic) ||
x.GetPropertyValue("eventDates").ToString().Contains(date) ||
x.GetPropertyValue("eventSummary").ToString().Contains(keyword)).OrderByDescending(x => x.CreateDate).ToList();
}
else
{
items = root.Children().Where(x => x.IsDocumentType("Event-Item")).OrderByDescending(x => x.CreateDate).ToList();
}
Does this look correct? Is there a better(more correct) way of doing this?
Any help greatly appreciated.

How about conditional where for each term?
string topic = Request.QueryString["topic"];
string date = Request.QueryString["date"];
string keyword = Request.QueryString["keyword"];
var filteredItems = root.Children()
.Where(x => x.IsDocumentType("Event-Item"));
if (!string.IsNullOrEmpty(topic))
filteredItems = filteredItems.Where(x => x.GetPropertyValue("eventTitle")
.ToString()
.Contains(topic));
if (!string.IsNullOrEmpty(date))
filteredItems = filteredItems.Where(x => x.GetPropertyValue("eventDates")
.ToString()
.Contains(date));
if (!string.IsNullOrEmpty(keyword))
filteredItems = filteredItems.Where(x => x.GetPropertyValue("eventSummary")
.ToString()
.Contains(keyword));
items = filteredItems.OrderByDescending(x => x.CreateDate).ToList();

I would break it down as follows. You are always filtering on "Event-Item", so take that out of the if/else and do it first. Then check for nulls and filter if needed. Finally, since you are always sorting, do that after everything.
var topic = Request.QueryString["topic"];
var date = Request.QueryString["date"];
var keyword = Request.QueryString["keyword"];
items = root
.Children()
.Where(x => x.IsDocumentType("Event-Item"));
if (!string.IsNullOrEmpty(topic) || !string.IsNullOrEmpty(date) || !string.IsNullOrEmpty(keyword))
{
items = items.Where(x =>
x.GetPropertyValue("eventTitle").ToString().Contains(topic) ||
x.GetPropertyValue("eventDates").ToString().Contains(date) ||
x.GetPropertyValue("eventSummary").ToString().Contains(keyword));
}
items = items.OrderByDescending(x => x.CreateDate);

How to attach a set of 'And' filters to a QueryOver query?

My method has a parameter which will determine which column to perform a where filter on, so to make things generic I need to be able to perform some logic on which column I want to perform the where on.
Is it possible to attach a .And clause to a given QueryOver<> query?
public List<..> GetABC(SomeType type)
{
NHibernateHelper.Session.QueryOver<Blah>()
.Where(x => x.name = "")
.And(x => x.a) // if type == SomeType.A then x.a, otherwise x.b (SomeType.B)
}
How could I do this?
I know when doing a criteria query I could create a criteria and then attach it to the query.

Sure.
var query = NHibernateHelper.Session.QueryOver<Blah>()
.Where(x => x.name = "");
if(type == SomeType.A)
{
query = query.And(x => x.a == ...);
}
else
{
query = query.And(x => x.b == ... );
}
The query will only be executed after the ".List()"
Update: I don't know if you're refering to something like this (in your comment)
var query = NHibernateHelper.Session.QueryOver<Blah>()
.Where(x => x.name = "");
Expression<Func<Blah, bool>> typePredicate = null;
if(type == SomeType.A)
{
typePredicate = x => x.a == ...;
}
else
{
typePredicate = x => x.b == ...;
}
query = query.Where(typePredicate);
Or probably you're more interested in something in the likes of Detached queries?

Not sure I completely understand the question ... but something like this?
public List<..> GetABC(SomeType type)
{
NHibernateHelper.Session.QueryOver<Blah>()
.Where(x => x.name = "")
.And(x => typeof(type) == SomeType.A ? x.a : x.b)
}