特性Attribute的简单用法

一、建立一个自定义的Attribute类

注：类名+Attribute，类需要继承Attribute

    /// <summary>
    /// 特性
    /// </summary>
    public class SensitiveFileTypeAttribute : Attribute
    {
        /// <summary>
        /// 字段类型
        /// </summary>
        public SensitiveFileTypeEnum FileType { get; set; }

        public SensitiveFileTypeAttribute(SensitiveFileTypeEnum fileType)
        {
            FileType = fileType;
        }

    }

    /// <summary>
    /// 字段类型枚举
    /// </summary>
    public enum SensitiveFileTypeEnum
    {

        /// <summary>
        /// 单价
        /// </summary>
        Price = 1,
        /// <summary>
        /// 金额
        /// </summary>
        Amount = 2,
        /// <summary>
        /// 折扣
        /// </summary>
        Discount = 3

    }

　　二、简单在属性上面使用特性：

    属性上面标注特性:[特性名(特性值)]

public class SaleSoDtlDto
    {
        /// <summary>
        /// 数量
        /// </summary>
        public int Qty { get; set; }

        /// <summary>
        /// 折扣
        /// </summary>
        [SensitiveFileType(SensitiveFileTypeEnum.Discount)]
        public decimal Discount { get; set; }

    
        /// <summary>
        /// 未税本币结算价
        /// </summary>
        [SensitiveFileType(SensitiveFileTypeEnum.Price)]
        public decimal SettlementPrice { get; set; }
           

        /// <summary>
        /// 含税本币结算金额
        /// </summary>
        [SensitiveFileType(SensitiveFileTypeEnum.Amount)]
        public decimal TaxSettlementAmount { get; set; }
         

    }

三、获取某一个类上面有某特性的所有属性：

    /// <summary>
    /// 导出敏感字段
    /// </summary>
    public static class SensitiveFileAppService
    {
        /// <summary>
        /// 使用反射找出某一个类有标记某特性的属性
        /// </summary>
        /// <typeparam name="T"></typeparam>
        public static List<PropertyInfo> GetSensitiveFileList<T>() where T : class, new()
        {
            List<PropertyInfo> proList = new List<PropertyInfo>();

            var properties = typeof(T).GetProperties();
            if (properties == null || !properties.Any()) return proList;

            foreach (PropertyInfo p in properties)
            {
                var name = p.Name;//属性名称

                var attribute = p.GetCustomAttribute<SensitiveFileTypeAttribute>();
                if (attribute == null) continue;  //当前属性是否有SensitiveFileTypeAttribute特性 为NULL就没有此属性

                var fileType = attribute.FileType;//特性的FileType属性值

                proList.Add(p);

            }

            return proList;

        }

    }

 public void TestWay()
        {

            var proList = SensitiveFileAppService.GetSensitiveFileList<SaleSoDtlDto>();
        }