我是C#的新手,我从Javascript开始,所以理解C#的行为有点困难。
我正在尝试在for循环中创建一个简单的对象然后显示指定的值,但是这有一个范围问题,并且我不知道如何在for循环之外访问它?
这是我的代码设置:
public class Player{
public int identity;
public int score;
public Player(int id){
identity = id;
score = 0;
}
}
for (int i = 0; i < max; i++){
Player player = new Player(i);
}
//here i want to access a player and print the information for said player
我不知道如何在循环之外访问新创建的玩家,这是怎么做到的?
答案 0 :(得分:3)
我可以理解这是如何混淆来自JavaScript,在JavaScript中所有变量都被提升到函数(或全局)范围。在C#中不是这样,C#变量通常在最近的{}
s范围内。但可以在儿童范围内使用。
所以你可以像这样写代码:
List<Player> players = new List<Player>();
Player player = null;
for (int i = 0; i < max; i++){
player = new Player(i);
players.Add(player);
}
Console.WriteLine(players[x]);
在此示例中,您可以访问player
之外的每个foreach
,因为它是在更高的范围内声明的。但这样写得更恰当:
List<Player> players = new List<Player>();
for (int i = 0; i < max; i++){
Player player = new Player(i);
players.Add(player);
}
Console.WriteLine(players[x]);
通常认为将变量声明为尽可能接近其使用范围是一种好习惯。
您自己建议的最终优化是完全消除player
声明(因为它是不必要的)并内联它。这给我们留下了最终版本:
List<Player> players = new List<Player>();
for (int i = 0; i < max; i++){
players.Add(new Player(i));
}
Console.WriteLine(players[x]);
答案 1 :(得分:2)
你可以尝试这样的事情
Player player = new Player();
List<Player> playerlist = new List<Player>();
for (int i = 0; i < max; i++){
player = new Player(i);
playerlist.Add(player);
}