c# - Object reference not set to an instance of an object -

public player(string name, list<card> cards) {    this.name = name;    try    {       this.stack.insertcards(cards);//here nullreferenceexeption    }    catch (exception e)    {                       throw e;    } }  public void insertcards(list<card> cards) {    stack.addrange(cards); }  public list<card> getsevencards() //the player gets cards function {    list<card> list = new list<card>();    int ran;    random r = new random();    (int = 0; < 7; i++)    {       ran = r.next(0, stack.count()-1);       list.add(stack[ran]);       stack.removeat(ran);    }    return list; } 

the stack gets cardlist of 7 cards

should be:

this.stack.insertcards(getsevencards()); 

and create new instance of stack.

because cards null. fill them function first.

can't more things, because didn't give more information definitions. there should more codes.