Linq Queries

Question

Make a List collection from two more List collections using Linq Query instead of Foreach. Ex : I have Two Collections like List ,List Integration above Collection and make a List 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?

Vulpes · Answer

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 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();

Vulpes · Answer

pulagara, Please start a new thread if you want to ask a new question. You'll have a better chance of getting a reply :)

pulagara murali · Answer

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?

pulagara murali · Answer

Thanks for Giving this Response....

pulagara murali · Answer

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 serviceDetails=new List (); 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 (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?

Vulpes · Answer

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.

Jean Paul · Answer

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

Linq Queries

Neeraja Sathyadas