What are 'closures' in .NET?

Question

What is a closure? Do we have them in .NET?

If they do exist in .NET, could you please provide a code snippet (preferably in C#) explaining it?

Answer 1

Just out of the blue,a simple and more understanding answer from the book C# 7.0 nutshell.

Pre-requisit you should know :A lambda expression can reference the local variables and parameters of the method in which it’s defined (outer variables).

    static void Main()
    {
    int factor = 2;
   //Here factor is the variable that takes part in lambda expression.
    Func multiplier = n => n * factor;
    Console.WriteLine (multiplier (3)); // 6
    }

Real part:Outer variables referenced by a lambda expression are called captured variables. A lambda expression that captures variables is called a closure.

Last Point to be noted:Captured variables are evaluated when the delegate is actually invoked, not when the variables were captured:

int factor = 2;
Func multiplier = n => n * factor;
factor = 10;
Console.WriteLine (multiplier (3)); // 30