var in class level members

Question

Hello experts,

 

I wonder why var is not allowed to be used in class level members. When using so, I am getting error as "The contextual keyword 'var' may only appear within a local variable declaration or in script code"

 

class ConcurrentDictionaryDemo
{
var phoneOrders = new ConcurrentDictionary<string, int>();  //Error

............

............

}

 

Any thoughts on this?