Namespace to implement LINQ

Shweta Kuthi

15y2.3kLINQ

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.

7 Replies

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Prabhu Raja15y ago
Accepted 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/

Understanding LINQ:

http://www.c-sharpcorner.com/UploadFile/logisimo/2256/

0
Jignesh Trivedi14y ago
Hi,

"var" key word only support if your targer framework is 3.0 or above.

hope this help.
0
Vulpes15y ago
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 };
0
Vipul Kelkar15y ago
hi shweta,lucy

what version of .net framework are u using ?
0
Priya Linge15y ago
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.
0
Lucy Jane15y ago
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.
0
Tulasi15y ago
can u post ur code ?
0