ZT-FJ-WMS/wms.util/Ext/EnumExt.cs

using AspectCore.Extensions.Reflection;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Reflection;

namespace wms.util.Ext
{
    public static class EnumExt
    {
        public static string GetDescription(this Enum obj)
        {
            var fi = obj.GetType().GetField(obj.ToString());
            var arrDesc = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
            return arrDesc[0]?.Description;
        }

        public static string GetDescription<T>(this Enum obj)
        {
            var refactor = typeof(T).GetField(obj.ToString()).GetReflector();
            var arrDesc = refactor.GetCustomAttributes(typeof(DescriptionAttribute));
            return ((DescriptionAttribute)arrDesc[0]).Description;
        }

        public static T ToEnum<T>(this string obj)
        {
            return (T)Enum.Parse(typeof(T), obj);
        }

        public static string GetDescription<T>(string obj)
        {
            var refactor = typeof(T).GetField(obj).GetReflector();
            var arrDesc = refactor.GetCustomAttributes(typeof(DescriptionAttribute));
            return ((DescriptionAttribute)arrDesc[0]).Description;
        }

        public static Dictionary<int, string> ToDict(this Enum obj)
        {
            var enumDict = new Dictionary<int, string>();
            foreach (int enumValue in Enum.GetValues(obj.GetType()))
            {
                enumDict.Add(enumValue, enumValue.ToString());
            }
            return enumDict;
        }

        public static List<string> ToList<T>()
        {
            //Type t = typeof(T);
            //var ty = t.GetFields(BindingFlags.Public | BindingFlags.Static)
            //.Where(p => t.IsAssignableFrom(p.FieldType))
            //.Select(pi => (T)pi.GetValue(null))
            //.ToList();
            return Enum.GetValues(typeof(T)).Cast<T>().Select(x => x.ToString()).ToList();
        }

        public static List<KeyValuePair<int, string>> ToKVList<T>()
        {
            var keys = new List<KeyValuePair<int, string>>();
            foreach (var e in Enum.GetValues(typeof(T)))
            {
                object[] objArr = e.GetType().GetField(e.ToString()).GetCustomAttributes(typeof(DescriptionAttribute), true);
                DescriptionAttribute da = objArr?[0] as DescriptionAttribute;
                keys.Add(new KeyValuePair<int, string>(Convert.ToInt32(e), da.Description));
            }
            return keys;
        }

        public static List<KeyValuePair<int, string>> ToKVListLinq<T>()
        {
            Type t = typeof(T);
            return t.GetFields(BindingFlags.Public | BindingFlags.Static)
        .Where(p => t.IsAssignableFrom(p.FieldType))
        .Select(a => new KeyValuePair<int, string>(Convert.ToInt32(a.GetValue(null)),
        (a.GetCustomAttributes(typeof(DescriptionAttribute), true)?[0] as DescriptionAttribute).Description)
        ).ToList();
        }

        /// <summary>
        /// 根据指定的属性返回集合中的非重复元素
        /// </summary>
        /// <typeparam name="TSource">数据源的类型</typeparam>
        /// <typeparam name="TKey">数据源需要进行筛选的属性</typeparam>
        /// <param name="source">数据源</param>
        /// <param name="keySelector">指定属性的函数表达式</param>
        /// <returns></returns>
        public static IEnumerable<TSource> DistinctBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
        {
            var seenKeys = new HashSet<TKey>();
            foreach (var source1 in source)
            {
                if (seenKeys.Add(keySelector(source1))) yield return source1;
            }
        }

        /// <summary>
        ///  两个参数任意一个不重复即可
        /// </summary>
        /// <typeparam name="TSource">数据源的类型</typeparam>
        /// <typeparam name="TKey1">数据源需要进行筛选的属性</typeparam>
        /// <typeparam name="TKey2">数据源需要进行筛选的属性</typeparam>
        /// <param name="source">数据源</param>
        /// <param name="keySelector1">指定属性的函数表达式</param>
        /// <param name="keySelector2">指定属性的函数表达式</param>
        /// <returns></returns>
        public static IEnumerable<TSource> DistinctBy<TSource, TKey1, TKey2>(this IEnumerable<TSource> source, Func<TSource, TKey1> keySelector1, Func<TSource, TKey2> keySelector2)
        {
            var seenKeys1 = new HashSet<TKey1>();
            var seenKeys2 = new HashSet<TKey2>();
            foreach (var source1 in source)
            {
                if (seenKeys1.Add(keySelector1(source1))) //第一属性不重复
                {
                    seenKeys2.Add(keySelector2(source1)); //将第一属性对应的第二属性计入HashSet，避免第二属性重复
                    yield return source1;
                }
                else if (seenKeys2.Add(keySelector2(source1))) yield return source1; //第一属性重复，第二属性不重复
            }
        }
    }
}