关于c＃：nullreferenceexception：对象引用未设置为对象的实例

nullreferenceexception : object reference not set to an instance of an object

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我有两个班级的球员和支持者。类播放器的一个字段是类支持程序的对象列表。当我试图将一个新对象添加到某个玩家的支持者列表中时，我得到了nullreferenceexception，我认为这是因为我从未初始化支持者列表，但我不知道在哪里以及如何初始化。下面是代码和类：

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public class Player
{
public string name { get; set; }
public int numMention { get; set; }

public double s { get; set; }
public double salience { get; set; }
public double supportForPlayer1 { get; set; }
public double supportForPlayer2 { get; set; }
public double supportDiff { get; set; }
public double position { get; set; }
public List<Supporter> supporters { get; set; }
}

public class Supporter
{
public string name { get; set; }
public double GFP { get; set; }
public double supportAmount { get; set; }
}

foreach (var val in playersList)
{
sql ="SELECT Actor2CountryCode,SUM(GoldsteinScale) AS SupportForPlayer2 FROM [gdelt-bq:full.events] WHERE Year>=" + predictionDate +" AND (Actor1Code='" + val.name +"' AND (Actor2Code!='" + val.name +"' AND Actor2Code!=' ')) GROUP BY Actor2CountryCode";

response = new WebClient().DownloadString(url +"?q=" + Uri.EscapeUriString(sql));
value = JsonValue.Parse(response);
result = value as JsonObject;

for (int i = 0; i < result["modelData"]["rows"].Count; i++)
{
row = result["modelData"]["rows"][i];

if (row["f"][0]["v"] != null && row["f"][1]["v"] != null)
val.supporters.Add(new Supporter { name = (string)row["f"][0]["v"], supportAmount = (double)row["f"][1]["v"], GFP = 0 });
else
val.supporters.Add(new Supporter { name ="NULL", supportAmount = 0, GFP = 0 });
}
}