Stat.cs

using System;
using System.Collections.Generic;
using System.IO;

namespace Stat
{
    public static class Program
    {
        private const string FILE_NAME = "Data.txt";
        private static readonly IDictionary<string, int> stat = new Dictionary<string, int>();

        public static void Main()
        {
            try
            {
                foreach (string line in File.ReadLines(FILE_NAME))
                {
                    if (string.IsNullOrWhiteSpace(line.Trim()))
                    {
                        continue;
                    }

                    if (stat.ContainsKey(line))
                    {
                        ++stat[line];
                    }
                    else
                    {
                        stat.Add(line, 1);
                    }
                }

                foreach (KeyValuePair<string, int> pair in stat)
                {
                    Console.WriteLine($"{pair.Key} : {pair.Value}");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"發生例外狀況 : {ex.Message}");
            }

            Console.Write("請按任意按鍵繼續 ... ");
            Console.ReadKey(true);
        }
    }
}