JSON 对象为空

Question

我成功反序列化了 JSON 文件，我得到了结果，但在结果结束后，我得到了“对象未设置为对象的实例”错误

JSON 文件：

"radiant_team": {
          "team_name": "EHOME",
          "team_id": 4,
          "team_logo": 52122954231169668,
          "complete": true
        },
        "dire_team": {
          "team_name": "Team Secret",
          "team_id": 1838315,
          "team_logo": 543025270456493033,
          "complete": true

public partial class LiveLeagues
{
    public LiveGames Result { get; set; }
}
public class LiveGames
{
    public List<GameStats> games { get; set; }
    public int status { get; set; }
}
 public class GameStats
        {
            public List<BasePlayer> players { get; set; }
            public RadiantTeam radiant_team { get; set; }
            public DireTeam dire_team { get; set; }
        }

public class DireTeam
    {
        public string team_name { get; set; }
        public int team_id { get; set; }
        public object team_logo { get; set; }
        public bool complete { get; set; }
    }

public class RadiantTeam
    {
        public string team_name { get; set; }
        public int team_id { get; set; }
        public object team_logo { get; set; }
        public bool complete { get; set; }
    }

LiveLeagues.LiveLeagues liveGames = JsonConvert.DeserializeObject<LiveLeagues.LiveLeagues>(response.Content.ReadAsStringAsync().Result);

    foreach (var leagues in liveGames.Result.games)
        {
           MessageBox.Show(leagues.dire_team.team_id.ToString());
           MessageBox.Show(leagues.radiant_team.team_id.ToString());  
        }

我尝试遍历 JSON 并测试这些值是否会显示。我在 MessageBox.Show 上测试了它，得到了结果 "EHOME" 和 "Team Secret" 但之后出现错误“对象未设置为对象的实例”

Answer 1

当 json 允许没有 dire_team and/or radiant_team 属性的游戏时，您应该进行空值检查以确保它们存在：

foreach (var leagues in liveGames.Result.games){ 
  if(leagues.dire_team != null)
    MessageBox.Show(leagues.dire_team.team_id.ToString());
  else
    MessageBox.Show("no dire team for this game");

  if(leagues.radiant_team != null)      
     MessageBox.Show(leagues.radiant_team.team_id.ToString());  
  else
    MessageBox.Show("no radiant team for this game");
}

或者您可以尝试在 GameStats 的构造函数中为这些对象使用默认值。

public class GameStats
    {
        public List<BasePlayer> players { get; set; }
        public RadiantTeam radiant_team { get; set; }
        public DireTeam dire_team { get; set; }

        public GameStats(){
          dire_team = new DireTeam();
          radiant_team = new RadiantTeam();
        }
    }

JSON 对象为空

JSON Object Null

c#

json

json-deserialization