C#应用 - 03.怎么对Dictionary进行排序

1. 对Dictionary进行排序主要利用了查询表达式LINQ。

using System;
using System.Collections.Generic;
using System.Linq;

namespace _03
{
    
    
    class Program
    {
    
    
        static void Main(string[] args)
        {
    
    
            Console.WriteLine("*****按添加顺序排列*****");
            Dictionary<object, object> dictionary = new Dictionary<object, object>();
            dictionary.Add(1, "c");
            dictionary.Add(3, "a");
            dictionary.Add(2, "b");
            foreach (var item in dictionary)
            {
    
    
                Console.WriteLine(item);
            }
            Console.WriteLine();

            Console.WriteLine("*****按Key升序排列*****");
            Dictionary<object, object> ascSortByKey = Test.AscSortByKey(dictionary);
            foreach (var item in ascSortByKey)
            {
    
    
                Console.WriteLine(item);
            }
            Console.WriteLine();

            Console.WriteLine("*****按Value升序排列*****");
            Dictionary<object, object> ascSortByValue = Test.AscSortByValue(dictionary);
            foreach (var item in ascSortByValue)
            {
    
    
                Console.WriteLine(item);
            }
            Console.WriteLine();

            Console.WriteLine("*****按Key降序排列*****");
            Dictionary<object, object> descSortByKey = Test.DescSortByKey(dictionary);
            foreach (var item in descSortByKey)
            {
    
    
                Console.WriteLine(item);
            }
            Console.WriteLine();

            Console.WriteLine("*****按Value降序排列*****");
            Dictionary<object, object> descSortByValue = Test.DescSortByValue(dictionary);
            foreach (var item in descSortByValue)
            {
    
    
                Console.WriteLine(item);
            }
            Console.WriteLine();
        }
    }

    class Test
    {
    
    
        /// <summary>
        /// 按Key升序排列
        /// </summary>
        /// <typeparam name="K"></typeparam>
        /// <typeparam name="V"></typeparam>
        /// <param name="dictionary"></param>
        /// <returns></returns>
        public static Dictionary<K, V> AscSortByKey<K, V>(Dictionary<K, V> dictionary)
        {
    
    
            var result = from obj in dictionary orderby obj.Key select obj;
            Dictionary<K, V> ascSortByKey = new Dictionary<K, V>();
            foreach (var item in result)
            {
    
    
                ascSortByKey.Add(item.Key, item.Value);
            }
            return ascSortByKey;
        }

        /// <summary>
        /// 按Value升序排列
        /// </summary>
        /// <typeparam name="K"></typeparam>
        /// <typeparam name="V"></typeparam>
        /// <param name="dictionary"></param>
        /// <returns></returns>
        public static Dictionary<K, V> AscSortByValue<K, V>(Dictionary<K, V> dictionary)
        {
    
    
            var result = from obj in dictionary orderby obj.Value select obj;
            Dictionary<K, V> ascSortByValue = new Dictionary<K, V>();
            foreach (var item in result)
            {
    
    
                ascSortByValue.Add(item.Key, item.Value);
            }
            return ascSortByValue;
        }

        /// <summary>
        /// 按Key降序排列
        /// </summary>
        /// <typeparam name="K"></typeparam>
        /// <typeparam name="V"></typeparam>
        /// <param name="dictionary"></param>
        /// <returns></returns>
        public static Dictionary<K, V> DescSortByKey<K, V>(Dictionary<K, V> dictionary)
        {
    
    
            var result = from obj in dictionary orderby obj.Key descending select obj;
            Dictionary<K, V> descSortByKey = new Dictionary<K, V>();
            foreach (var item in result)
            {
    
    
                descSortByKey.Add(item.Key, item.Value);
            }
            return descSortByKey;
        }

        /// <summary>
        /// 按Value降序排列
        /// </summary>
        /// <typeparam name="K"></typeparam>
        /// <typeparam name="V"></typeparam>
        /// <param name="dictionary"></param>
        /// <returns></returns>
        public static Dictionary<K, V> DescSortByValue<K, V>(Dictionary<K, V> dictionary)
        {
    
    
            var result = from obj in dictionary orderby obj.Value descending select obj;
            Dictionary<K, V> descSortByValue = new Dictionary<K, V>();
            foreach (var item in result)
            {
    
    
                descSortByValue.Add(item.Key, item.Value);
            }
            return descSortByValue;
        }
    }
}