c# - Eager Loading with Entity Framework, LINQ -

i working on asp.net mvc project. using ef code-first approach. have 3 classes, are:

public class {     public int aid {get;set;}     public string a1 {get;set}     public string a2 {get;set}      public virtual list<b> bs {get;set;} }  public class b {     public int bid {get;set;}     public string b1 {get;set}     public string b2 {get;set}      public aid {get;set}     public virtual a {get;set}      public virtual list<c> cs {get;set;} }  public class c {     public int cid {get;set;}     public string c1 {get;set}     public string c2 {get;set}      public bid {get;set}     public virtual b b {get;set} } 

i want select c1 properties of class c based on class b a1 = 4 . tried using:

var result = db.c.select(x=>x.c1).include(x=>b).where(x=>x.a.equals(4)) 

i confused , don't know how execute linq query. not sure whether continue using eager loading or fall on else.

please can guru me out please?

try this:

var result = db.c     .where(c => c.b.a.a1 == 4)     .select(c => c.c1)     .tolist() 

you don't have use eager loading (include) here because none of nested entities contained in result.

eager loading used workaround select n + 1 problem. problem arises when retrieve parent entity , want iterate through children. results in n + 1 requests made database.

here code samples illustrate:

without eager loading

var carlist = db.cars.tolist(); //this create 1 request database retrieve cars  foreach(var car in carlist) {     foreach(var wheel in car.wheels) //this line create request database retrieve wheels specific car     }         console.write("car = {0}, wheel = {1}", car, wheel);     } } //total requests: 1 car list + n requests retrieve wheels n - total number of cars 

with eager loading

var carlist = db.cars.include(x => x.wheels).tolist(); //this create 1 request database retrieve cars information wheels  foreach(var car in carlist) {     foreach(var wheel in car.wheels) //this line won't create request database because data has been loaded using eager loading     }         console.write("car = {0}, wheel = {1}", car, wheel);     } } //total requests: 1 car list wheel information