Linq Queries

Question

Make a List<T> collection from two more List<T> collections using Linq Query instead of Foreach.

Ex : I have Two Collections like List<Registration> ,List<Patient>
Integration above Collection and make a List<ServiceDetails> Collection.
For this I am using Foreach and form the collection ,
But I need Linq Query to make the same scenario.

Can any one give me Idea on above Query?

Answer 1

I'm not sure that it's a good idea to write a LINQ query which just changes the state of existing objects and then adds them to a List but, if you must do it, then I'd try this:

List<ServiceDetail> serviceDetails = ServiceDetails 

.Where(serviceItem =>

{

  serviceItem.Patient = Patients.Where(i => i.PatientId == serviceItem.PatientId).FirstorDefault();

  serviceItem.Registration = Registrations.Where(i => i.RegistrationId == serviceItem.RegistrationId).FirstorDefault();

  return true; // select everything regardless

})

.ToList();

Answer 2

pulagara,

Please start a new thread if you want to ask a new question.

You'll have a better chance of getting a reply :)

Answer 3

Hi,

I have one more query , how to pass parameters from Silverlight to Asp.net(without querystring and Initparameters)?

Could you give me any Idea?

Answer 4

Thanks for Giving this Response....

Answer 5

Thanks for Response,

I have a Collection like ServiceDetails. It Contains 

Patient Object and Registration Object

ServiceDetail serviceDetail=new ServiceDetail ();
serviceDetail.Patient=new Patient();
serviceDetail.Registration=new Registration();

ServiceDetails(serviceDetail);

Above Is my Objct Formation.

In this case I have Two Other Collections Like 'Patients' and 'Registrations'

For above Object formation I wrote like below
 
List<ServiceDetail> serviceDetails=new List<ServiceDetail>();
foreach(ServiceDetail serviceItem in ServiceDetails)
{
          //Bind Patient Object
        serviceItem.Patient=Patients.where(i=>i.patientid==serviceItem.patientid)
                                        .firstorDefault();
          //Bind Registration Object
        serviceItem.Registration=Registrations.where(i=>i.registrationId==serviceItem.registrationid)
                                        .firstorDefault();
        serviceDetails.add(serviceItem);

}

  ServiceDetails=new List<ServiceDetail>(serviceDetails); 
  
 For above collection formation I used one foreach. My query is I don,t used even one foreach also to make a Collection, instead of foreach I want to use Lamda expression or Linq Query .

Could you give any Idea on this Query Please?

Answer 6

It's impossible for any one to answer this question unless you tell us what the relationship is between the Patient, Registration and ServiceDetails classes.

Jean's made a good guess that the first two inherit from the third but another possibility is that a ServiceDetails object is somehow constructed from instances of the other two classes.

Answer 7

Hello Murali,

I can provide a solution in which the above typed lists are casted to object.
(I believe the classes Registration and Patient are deriving from ServiceDetails)

            List<Registration> l1 = new List<Registration>();

            List<Patient> l2 = new List<Patient>();

            List<ServiceDetails> l3 = new List<ServiceDetails>();

            l3.AddRange(l1.Cast<ServiceDetails>());

            l3.AddRange(l2.Cast<ServiceDetails>());

The above code is in Lambda..

If the classes are not having base as ServiceDetail, you may declare an implicit operator overloading like..
(but not sure it will fit the above code)

 public class Patient

    {

        public static implicit operator ServiceDetail(Patient p)

        {

            return new ServiceDetail();

        }

    }

Regards,
JP