Asp.Net Core 下 Newtonsoft.Json 转换字符串 null 替换成string.Empty

public class NullToEmptyStringResolver : DefaultContractResolver
    {
        /// 

        /// 创建属性
        /// 
        /// 类型
        /// 序列化成员
        /// 
        protected override IList CreateProperties(Type type, MemberSerialization memberSerialization)
        {
            return type.GetProperties()
                .Select(x =>
                {
                    var property = CreateProperty(x, memberSerialization);
                    property.ValueProvider = new NullToEmptyStringValueProvider(x);
                    return property;
                }).ToList();
        }

        /// 
        /// 

        /// 小写
        /// 
        /// 
        /// 
        protected override string ResolvePropertyName(string propertyName)
        {
            return propertyName.ToLower();
        }
    }

public class NullToEmptyStringValueProvider : IValueProvider
    {
        private readonly PropertyInfo _memberInfo;

        /// 

        /// 构造函数
        /// 
        /// 
        public NullToEmptyStringValueProvider(PropertyInfo memberInfo)
        {
            _memberInfo = memberInfo;
        }

        /// 
        /// 

        /// 获取Value
        /// 
        /// 
        /// 
        public object GetValue(object target)
        {
            var result = _memberInfo.GetValue(target);
            if (_memberInfo.PropertyType == typeof(string) && result == Convert.DBNull)
            {
                result = string.Empty;
            }

            return result;

        }

        /// 
        /// 

        /// 设置Value
        /// 
        /// 
        /// 
        public void SetValue(object target, object value)
        {
            _memberInfo.SetValue(target, value);
        }
    }

 

 出处：

https://www.cnblogs.com/FanTaoLin/p/10081891.html