我在C#中收到錯誤“命名空間中不存在類型或命名空間名稱”。我到處檢查，但它沒有解決我的問題，這里是主程序using System;using System.Collections.Generic;using System.Security.Cryptography;using System.Text;using Newtonsoft.Json;using BlockChainMySelf;using Formatting = Newtonsoft.Json.Formatting;namespace BlockChainMySelf{    class Program    {        static void Main(string[] args)        {            var startTime = DateTime.Now;            BlockChainMySelf.BlockChain StepCoin = new BlockChain();            StepCoin.CreateTransaction(new Transaction("Henry", "MaHesh", 10));            StepCoin.CreateTransaction(new Transaction("lkjsdf", "MaADLKHesh", 15));            StepCoin.CreateTransaction(new Transaction("Henry", "MaHesh", 20));            StepCoin.CreateTransaction(new Transaction("Henry", "MaHesh", 60));            StepCoin.ProcessPendingTransactions("Bill");這是我想調用的類using System;using System.Collections.Generic;using System.Security.Cryptography;using System.Text;using Newtonsoft.Json;using BlockChainMySelf;using Formatting = Newtonsoft.Json.Formatting;namespace BlockChainMySelf{    public class BlockChain    {        IList<Transaction> PendingTransactions = new List<Transaction>();        public IList<Block> Chain { set; get; }        public int Difficulty { set; get; } = 2;這是屏幕截圖主要類答案問題答案問題2