C# LINQ Target needs to be static

Question

In the following code, why is it necessary for the array (arr) to be static ?

If I remove static, then it is no more visible for using in the LINQ query.

class A
{
     static int[] arr = { 1, 2, 3, 4 };
     IEnumerable<int> result = from i in arr where i < 10 select i;
}

Thanks.

Answer 1

You cannot access other class instance variables if you directly initialize variables using a variable initializer - you could move the code to the constructor instead:

class A
{
     int[] arr = { 1, 2, 3, 4 };
     IEnumerable<int> result;

     public A()
     {
         result = from i in arr where i < 10 select i;
     }
}

From the C# spec, 10.5.5.2 Instance field initialization:

A variable initializer for an instance field cannot reference the instance being created. Thus, it is a compile-time error to reference this in a variable initializer, as it is a compile-time error for a variable initializer to reference any instance member through a simple-name.

This makes sense, since variable initializers are executed before the base class constructor, hence the class instance has not been fully "constructed" yet.