Namespace to implement LINQ

Question

I created a program to implement LINQ and i am using var keyword for object Initializers, but the var keyword is not supporting, Can anyone tell me which namespace should i include to implement Type refrencing with LINQ.

Prabhu Raja · Answer

Hi, i have given an example below. using System; using System.Linq; public sealed class Program { static double Square( double n) { Console .WriteLine( "Computing Square(" + n + ")..." ); return Math .Pow(n, 2); } public static void Main() { int [] numbers = { 1, 2, 3 }; var query = from n in numbers select Square(n); foreach ( var n in query) Console .WriteLine(n); } } OUTPUT: Computing Square(1)... 1 Computing Square(2)... 4 Computing Square(3)... 9 And you may try the following Articles : Syntaxes and Clauses in LINQ; http://www.c-sharpcorner.com/UploadFile/ravi_panara/4520/ U nderstanding LINQ: http://www.c-sharpcorner.com/UploadFile/logisimo/2256/

Jignesh Trivedi · Answer

Hi, "var" key word only support if your targer framework is 3.0 or above. hope this help.

Vulpes · Answer

Shweta/Lucy, 'var' is a keyword within the C# language; it tells the compiler to infer the type of the variable from the expression which is assigned to it. It is nothing to do with LINQ as such but is commonly used with it. The reason why you're getting the error message is because 'var' can't be used to declare a field (i.e. a class level variable). It can only be used to declare local variables within a method or property. Also, even if you change your code to: public class student { public string Name { get; set; } public int Roll_no { get; set; } student v = new student { Name = "shweta", Roll_no = 10 }; } then, as soon as you do this: student s = new student(); you'll get a stack overflow exception because the definition of the student class is circular. What you really need is this: public class student { public string Name { get; set; } public int Roll_no { get; set; } } and you can then intstantiate it as follows from within some method: var v = new student { Name = "shweta", Roll_no = 10 };

Vipul Kelkar · Answer

hi shweta,lucy what version of .net framework are u using ?

Priya Linge · Answer

Hi, Please see below link. http://www.dotnetperls.com/var Namespace : using System.Linq; public Form2() { InitializeComponent(); var v = new student { Name = "Sheena", Roll_no = 10 }; } public class student { public string Name { get; set; } public int Roll_no { get; set; } } Hope this will help you. Thanks.

Lucy Jane · Answer

Actually i am a begineer and learning LINQ, public class student { public string Name { get ; set ; } public int Roll_no { get ; set ; } var v = new student { Name = "shweta" , Roll_no = 10 }; } Here var keyword is not Identifiable.

Tulasi · Answer

can u post ur code ?

Namespace to implement LINQ

Answers (7)