I want to Read Related Data but only read the specific field.
if use include theninclude will read all fiedl.
so I use .Select, but how to use .Select to achieve .ThenInclude?
Thanks~
var ViewModel = await _context.A_Table
.Select(s => new ViewModel {
A_TableId = s.Id,
B_Table = s.B_Table,
C_Table = ??? (s.B_Table.C_Table is wrong)
});
public class A_Table
{
public int Id { get; set; }
public string Field1 { get; set; }
public IList<B_Table> B_Table { get; set; }
}
public class B_Table
{
public int Id { get; set; }
public string Field1 { get; set; }
public int A_TableId { get; set; }
public int C_TableId { get; set; }
public C_Table C_Table { get; set; }
}
public class C_Table
{
public int Id { get; set; }
public string Field1 { get; set; }
public B_Table B_Table { get; set; }
}
this is because B_Table property is list of B_Table so when you want to access C_Table property inside it you have to specify which item in the list you want to access
e.g. s.B_Table[0].C_Table to access first item in the list.
if you want aggregate all items in side the list you can use SelectMany using Linq inside namespace System.Linq
e.g. s.B_Table.SelectMany(B_Table => B_Table.C_Table).ToList()
Related
I'm trying to bring a listing to frontEnd.
I'm using mongoDb. My mongodb has a colletion called Employee. Employee has the following attribute
public class EmployeeViewModel
{
[BsonId(IdGenerator = typeof(StringObjectIdGenerator))]
public string ownerId { get; set; }
public string atributeChange { get; set; }
public PersonalDataViewModel personalData { get; set; }
public AddressViewModel address { get; set; }
public List<EmailsViewModel> emails { get; set; }
public SyndicateViewModel syndicate { get; set; }
public List<DependentsViewModel> dependents { get; set; }
public List<PhoneViewModel> phone { get; set; }
public List<BankViewModel> bank { get; set; }
public AttributesViewModel attributes { get; set; }
public List<BenefitsViewModel> benefits { get; set; }
public TransportViewModel transport { get; set; }
public List<AttachmentsViewModel> attachments { get; set; }
public List<DocumentsViewModel> documents { get; set; }
public List<DocumentsImagesViewModel> DependentsDocuments { get; set; }
public List<AttachmentsViewModel> DependentsAttachments { get; set; }
public List<BenefitsViewModel> DependentsBenefits { get; set; }
}
In this Model, I have an attribute called: public List <DocumentsImagesViewModel> DependentsDocuments {get; set; }:
public class DocumentsViewModel
{
[BsonId]
public string ownerId { get; set; }
public string id { get; set; }
public string dependentId { get; set; }
public string number { get; set; }
public DateTime expiration { get; set; }
public List<DocumentsImagesViewModel> images { get; set; }
public List<DocumentPropertiesViewModel> properties { get; set; }
public DocumentTypeViewModel type { get; set; }
}
I'm trying to bring benefits that contain the depedentID equal of the parameter. When I use this method, it has an error that can not be converted. IEnumerable to List C #
public async Task<List<Documents>> GetDocument(string ownerId, string dependentId)
{
var query = from employee in _employee.AsQueryable()
where employee.ownerId == ownerId
select new Employee()
{
DependentsDocuments = employee.DependentsDocuments.Where(x => x.dependentId == dependentId)
};
return query.ToList();
}
What is the best way to get this data? this filter?
I used this question as a reference: Mongodb C# driver return only matching sub documents in array
LINQ's .Where returns IEnumerable<T>, your model expects a List<T>, you can either change your model to IEnumerable<T> or you can change this line of code:
DependentsDocuments = employee.DependentsDocuments
.Where(x => x.dependentId == dependentId)
to this:
DependentsDocuments = employee.DependentsDocuments
.Where(x => x.dependentId == dependentId)
.ToList()
changing your code to this one maybe it work:
public async Task<List<Documents>> GetDocument(string ownerId, string dependentId)
{
var query = (from employee in _employee.AsQueryable()
where employee.ownerId == ownerId
select new Employee()
{
DependentsDocuments = employee.DependentsDocuments.Where(x => x.dependentId == dependentId).ToList()
}).ToList();
return query.ToList();
}
i have a list of objects
public int id { get; set; }
public string device_code { get; set; }
public string device_type { get; set; }
public string authentication_token { get; set; }
public string Status { get; set; }
while returning the list i want to remove "device_code" and "device_type" from the list and return the list only with "id","authentication_token" and "status".
How can I delete certain objects?
You must cast your object to another type that will contain only needed properties.
You can do this easy with linq:
var result = yourCollection.Select(x => new YourTempClass(){property1=x.property1});
You seem to not want to remove objects, but properties of the objects.
public class ClassWithAllProperties
{
public int id { get; set; }
public string device_code { get; set; }
public string device_type { get; set; }
public string authentication_token { get; set; }
public string Status { get; set; }
}
var allInstances = new List<ClassWithAllProperties>();
// populate list
var allInstancesButNotAllProperties = allInstances.Select(x => new { id = x.id, authentication_token = x.authentication_token, Status = x.Status }).ToList();
Now this list contains only the properties you want. However it obviously also does not contain instances of ClassWithAllProperties. It contains so-called anonymous classes. Classes the compiler builds in the background for you, based on your description in the new.
It's simple, create another class containing properties that are required and then return its object using the list you have created.
Original Class
public class Data {
public int id { get; set; }
public string device_code { get; set; }
public string device_type { get; set; }
public string authentication_token { get; set; }
public string Status { get; set; }
}
Class That will be returned
public class DataTobeReturned {
public int id { get; set; }
public string authentication_token { get; set; }
public string Status { get; set; }
}
Suppose you have list like
List<Data> list = // some data;
You can do
List<DataTobeReturned> list2 = list.Select(x => new DataTobeReturned { x.id, x.Status, x.authentication_token}).ToList();
Simply return the list2 object.
If you have this class:
class MyClass
{
public int id { get; set; }
public string device_code { get; set; }
public string device_type { get; set; }
public string authentication_token { get; set; }
public string Status { get; set; }
}
...and you have a list of them...
List<MyClass> list;
You can extract just the properties you want into an anonymous type by using LINQ:
var justWhatIWant = list.Select( a => new
{
id = a.id,
authentication_token = a.authentication_token,
Status = a.Status
});
The anonymous type isn't interface-compatible with anything, but you could use it to, say, create some JSON.
I need to pull a specific value from a nested object without using a foreach loop. I think the right approach here is a linq query, but I'm unable to grab the value I need. Considering the class structure:
public class Order
{
public int OrderID { get; set; }
public List<OrderItems> { get; set; }
}
public class OrderItems
{
public int OrderItemID { get; set; }
public string ItemName { get; set; }
public int Quantity { get; set; }
public List<OrderItemShipping> OrderItemShippings { get; set; }
}
public class OrderItemShipping
{
public int OrderItemShippingID { get; set; }
public Address ShipAddress { get; set; }
public class Address
{
public int AddressID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Address1 { get; set; }
public string City { get; set; }
public string State { get; set; }
public string PostalCode { get; set; }
}
I want to be able to do something like:
var shipToAddress = Order.OrderItems.OrderItemShipping.FirstOrDefault(x => x.Address.Address1);
But my syntax must not be correct, because I'm unable to grab the value I need?
If you need to access items of (nested) collections SelectMany is your friend:
var shipToAddress = Order.OrderItems
.SelectMany(oi => oi.OrderItemShipping.Select(ois => ois.ShipAddress.Address1)))
.FirstOrDefault();
Your syntax was wrong because the overload of FirstOrDefault expects a predicate(so a function that returns a bool) but you were passing: FirstOrDefault(x => x.Address.Address1).
If you need to filter it somehow("specific value from a nested object") you need to explain your requirement more precisely.
Below is the Entity class
public partial class TestPlanViewModel
{
public TestPlanViewModel()
{
this.TestPlanTestPoints = new List<TestPlanTestPoint>();
}
public int TestPlanId { get; set; }
public string TestPlanName { get; set; }
public virtual IList<TestPlanTestPoint> TestPlanTestPoints { get; set; }
}
public class TestPlanTestPoint
{
public int OrganizationId { get; set; }
public int TestPlanId { get; set; }
public string TestPlanName { get; set; }
public int TestPlanVersion { get; set; }
public int TestPointId { get; set; }
public string TestPointName { get; set; }
}
I need to write a query where I need to get the collections from the dbContext like,
var query = (from tpm in TestPlanMaster
join tptp in TestPlanTestPoint on tpm.TestPlanId equals tptp.TestPlanId
join tmm in TestMethodMaster on tptp.TestMethodId equals tmm.TestMethodId
join tpma in TestPointMaster on tptp.TestPointId equals tpma.TestPointId
select new
{
//Plan Details
tpm.TestPlanId,
tpm.TestPlanName,
}).ToList().Select(x => new Entities.CustomEntities.TestPlanViewModel ====> Custom Entity
{
TestPlanId = x.TestPlanId,
TestPlanName = x.TestPlanName,
TestPlanTestPoints = ?????? ==> how to fill this collection
});
As shown above the TestPlanTestPoints is the IList collection object. I need to populate the data with the values from TestPlanTestPoint table.
Any suggestions?
Model
TestPlan
public partial class TestPlanMaster
{
[DataMember]
public int TestPlanId { get; set; }
[DataMember]
public short TestPlanVersion { get; set; }
[DataMember]
public int OrganizationId { get; set; }
[DataMember]
public short TestPlanTypeId { get; set; }
[DataMember]
public string TestPlanName { get; set; }
}
TestPlanTestPointMapping Model
public partial class TestPlanTestPointMapping
{
[DataMember]
public int OrganizationId { get; set; }
[DataMember]
public int TestPlanId { get; set; }
[DataMember]
public short TestPlanVersion { get; set; }
[DataMember]
public int TestPointId { get; set; }
}
You are thinking too much sql, think more linq. You want to select "tpm" items, so just write a select of those and select the new TestPlanViewModel and fill its properties and navigational properties.
I'm assuming you have a TestPlanTestPoints navigational property in your TestPlanMaster.
var q = (from tpm in TestPlanMaster
select new TestPlanViewModel
{
TestPlanId = tpm.TestPlanId,
TestPlanName = tpm.TestPlanName,
TestPlanPoints = TestPlanTestPoint.Where(pr => tpm.TestPlanId == pr.TestPlanId).Select(tptp => new TestPlanTestPoint()
{
// Fill properties here
}
}).ToList();
I've been trying to find an answer to this on google and on SO
but everywhere I have found uses anonymously typed result lists
what I am trying to acheive is to take a List<SecondaryStandard>
and create a grouped List of SecondaryStandard
each SecondaryStandard looks like this
public class SecondaryStandard
{
public string Id { get; set; }
public int IdNumeric { get; set; }
public string IdText { get; set; }
public Sample Sample { get; set; }
public string StandardName { get; set; }
public DateTime DateCompleted { get; set; }
public SamplePoint SamplingPoint{ get; set; }
public Instrument Instrument{ get; set; }
public string ContainerId { get; set; }
public double Value { get; set; }
public string ComponentName { get; set; }
public string PointLocation { get; set; }
public string Description { get; set; }
public string Description2 { get; set; }
public string Analysis { get; set; }
public string Units { get; set; }
}
what i want is a List() where the Value Property is an average of results for each ComponentName.
Any ideas on how I could achieve this in a strongly typed way or do I need to suck it up and use anonymous objects to achieve what I'm looking for?
You mean this?
List<SecondaryStandard> list = new List<SecondaryStandard>();
// populate list
List<SecondaryStandard> result = list
.GroupBy(l => l.ComponentName)
.Select(s => new SecondaryStandard() { ComponentName = s.Key, Value = s.Average(x => x.Value) }).ToList();