C#：添加到列表会导致空引用异常

Question

我正在尝试在 C# 中使用类似字符串列表的东西。数据格式：科名：树木价值：[香蕉、印楝、木瓜、椰子]====科名：动物值：[猫、狗、猪、虎狮]我试过的代码：[DataContract(Name = "FamilyValuesMap", Namespace = "")]    public class FamilyValuesMap    {        [DataMember(Name = "FamilyName", Order = 1)]        public string FamilyName { get; set; }        [DataMember(Name = "Values", Order = 2)]        public List<string> Values { get; set; }    }    [CollectionDataContract(Name = "FamilyValuesMaps", ItemName = "FamilyValuesMap", Namespace = "")]    public class FamilyValuesMaps : List<FamilyValuesMap>    {    }在下面的代码中，我试图将条目推送到 FamilyValuesMaps，var FamilyValuesMaps = new FamilyValuesMaps();FamilyValuesMaps.Add(new FamilyValuesMap { FamilyName = "Trees", Values = { "Banana", "Neem", "Pappaya", "Coconut" } });我不确定混乱发生在哪里并且代码不起作用它返回以下错误。Data: {System.Collections.ListDictionaryInternal}HResult: -2147467261HelpLink: nullInnerException: nullMessage: "Object reference not set to an instance of an object."Source: nullStackTrace: nullTargetSite: null任何建议或想法会有所帮助？