特性（Attribute）

1.枚举获取特性，转换值

using System;
using System.Reflection;

namespace MyAttribute
{
    public static class HelloExtesion
    {
        public static string GetStr(this Enum e)
        {
            Type type = typeof(UserState);
            FieldInfo p = type.GetField(e.ToString());
            if (p.IsDefined(typeof(CSAttribute), true))
            {
                CSAttribute cs = p.GetCustomAttribute(typeof(CSAttribute)) as CSAttribute;
                return cs.Name;
            }
            else
            {
                return e.ToString();
            }
        }
    }
    public enum UserState
    {
        [CS("富人")]
        Rich = 1,
        [CS("一般人")]
        Normal = 2,
        //[CS("穷人")]
        Poor = 3,
    }
    public class CSAttribute : Attribute
    {
        public string Name { set; get; }
        public CSAttribute(string Name)
        {
            this.Name = Name;
        }
    }
}

 

2.特性验证字段格式

using HomeWork1.AttributeModels;
using System;
using System.Reflection;

namespace HomeWork1.Tool
{
    public static class ValidateTool
    {
        public static void ValidateEntity<T>(this T t) where T : class
        {
            Type type = typeof(T);
            foreach (var prop in type.GetProperties())
            {
                if(prop.IsDefined(typeof(AbstractAttribute),true))
                {
                    foreach (AbstractAttribute item in prop.GetCustomAttributes(typeof(AbstractAttribute)))
                    {
                        string s = item.Validate(prop.GetValue(t));
                        if (!string.IsNullOrEmpty(s))
                        {
                            throw new Exception($"{prop.GetChinese()}({prop.Name}):{s}");
                        }
                    }
                }
            }
        }
        public static string GetColumnName(this PropertyInfo Prop)
        {
            if (Prop.IsDefined(typeof(ColumnAttribute), true))
            {
                return (Prop.GetCustomAttribute(typeof(ColumnAttribute)) as ColumnAttribute).Name;
            }
            return Prop.Name;
        }
        public static string GetTableName(this Type type)
        {
            if (type.IsDefined(typeof(TableNameAttribute), true))
            {
                return (type.GetCustomAttribute(typeof(TableNameAttribute)) as TableNameAttribute).Name;
            }
            return type.Name;
        }
        public static string GetChinese(this PropertyInfo Prop)
        {
            if (Prop.IsDefined(typeof(ChineseAttribute), true))
            {
                return (Prop.GetCustomAttribute(typeof(ChineseAttribute)) as ChineseAttribute).Name;
            }
            return Prop.Name;
        }
    }
}