C# 如何从npgsql反序列化geojson多边形

我在尝试使用ef core 3.1获取实体表单npgsql时遇到以下异常

System.NotSupportedException: Deserialization of reference types without parameterless constructor is not supported. Type 'GeoJSON.Net.Geometry.Polygon'

我的实体：

    public class VoteEntity : IVoteEntity
    {
        public Guid Id { get; set; }
        [Column(TypeName = "jsonb")]
        public Polygon Coordinates { get; set; }
    }

---

异常的意思是-您的实体中需要一个无参数构造函数

因此，您的实体应为：

public class VoteEntity : IVoteEntity
{
    public Guid Id { get; set; }
    [Column(TypeName = "jsonb")]
    public Polygon Coordinates { get; set; }
    
    //constructor
    public VoteEntity ()
    {
      //you might want to initialise your properties here
    }
}

---

异常的意思是-您的实体中需要一个无参数构造函数

因此，您的实体应为：

public class VoteEntity : IVoteEntity
{
    public Guid Id { get; set; }
    [Column(TypeName = "jsonb")]
    public Polygon Coordinates { get; set; }
    
    //constructor
    public VoteEntity ()
    {
      //you might want to initialise your properties here
    }
}