如何在集合中保存具有多個變量類型的對象以稍後調用？

Question

我正在創建一個小程序，它接受用戶輸入（字符串和小數），並在菜單中選擇「查看摘要」選項時將其打印回用戶。

菜單根據用戶輸入循環切換，帳戶名稱/帳戶餘額將在請求/輸入後立即打印，但是一旦選擇了選項3，我就無法保存並打印它們。儘管有任何投入，「視圖總結」表示資產爲0，債務爲0。

Account類有一個字符串名稱和十進制餘額，我只希望它保存到用戶完成。 （無數據庫只是試圖讓概念現在）

我的主要問題：
這是因爲循環/應該名單是他們之外捕獲數據？
字典是一個更好的主意，我可以從一個空集合開始？

static void Main(string[] args) 
{ 
    string menuChoice; 
    string response; 

    do 
    { 
     // Welcome/Menu screen 
     Console.WriteLine("\nWelcome to your Net Worth Calculator.\n \n MENU:\n 1. Add Asset\n 2. Add Debt\n 3. View Summary"); 
     Console.WriteLine(" "); 
     Console.WriteLine("What would you like to do?\nPlease make a selection: "); 

     menuChoice = Console.ReadLine(); 

     Account asset = new Account(); 
     var accountList = new List<Account>(); 

     if (menuChoice == "1") 
     { 
      do 
      { //D1 
       Console.WriteLine("\nGreat! Let's add an account."); 
       Console.WriteLine("Account name:"); 
       asset.name = Console.ReadLine(); 
       Console.WriteLine("Your account name is: " + asset.name); 

       Console.WriteLine("\nWhat is your current account balance with " + asset.name + "?"); 
       Console.WriteLine("Balance:"); 
       asset.balance = Decimal.Parse(Console.ReadLine()); 

       accountList.Add(asset); 

       Console.WriteLine("Your balance with " + asset.name + " is currently $" + asset.balance + "."); 

       Console.WriteLine("\n\nWould you like to add another account? y/n"); 
       response = Console.ReadLine(); 
      } while (response != "n"); 

     } 

     if (menuChoice == "3") 
     { 
      //D3 
      Console.WriteLine("Let's take a look at the accounts and balances that you've added so far:"); 
      Console.WriteLine($"{asset.balance} is your asset, and {debt.balance} is your debt."); 
      decimal netWorth = asset.balance - debt.balance; 
      Console.WriteLine(netWorth); 

      Console.WriteLine($"{ asset.balance}"); 
      Console.WriteLine("\n\nWould you like to add another account? y/n"); 
      response = Console.ReadLine(); 
     } 

Answer 1

爲accountList必須輸入外循環，這樣就沒有哪個選項被選中的事，你都可以訪問它（讀或寫）。

事情是這樣的：

static void Main(string[] args) 
{ 
    string menuChoice; 
    string response; 
    var accountList = new List<Account>(); 

    // Welcome/Menu screen 
    Console.WriteLine("\nWelcome to your Net Worth Calculator.\n \n MENU:\n 1. Add Asset\n 2. Add Debt\n 3. View Summary"); 
    do 
    { 
     Console.WriteLine(" "); 
     Console.WriteLine("What would you like to do?\nPlease make a selection: "); 

     menuChoice = Console.ReadLine(); 

     if (menuChoice == "1") 
     { 
      do 
      { //D1 
       Account asset = new Account(); 
       Console.WriteLine("\nGreat! Let's add an account."); 
       Console.WriteLine("Account name:"); 
       asset.name = Console.ReadLine(); 
       Console.WriteLine("Your account name is: " + asset.name); 

       Console.WriteLine("\nWhat is your current account balance with " + asset.name + "?"); 
       Console.WriteLine("Balance:"); 
       asset.balance = Decimal.Parse(Console.ReadLine()); 

       accountList.Add(asset); 

       Console.WriteLine("Your balance with " + asset.name + " is currently $" + asset.balance + "."); 

       Console.WriteLine("\n\nWould you like to add another account? y/n"); 
       response = Console.ReadLine(); 
      } while (response != "n"); 

     } 

     if (menuChoice == "3") 
     { 
      //D3 
      Console.WriteLine("Let's take a look at the accounts and balances that you've added so far:"); 
      Console.WriteLine($"{asset.balance} is your asset, and {debt.balance} is your debt."); 
      decimal netWorth = asset.balance - debt.balance; 
      Console.WriteLine(netWorth); 

      Console.WriteLine($"{ asset.balance}"); 
      Console.WriteLine("\n\nWould you like to add another account? y/n"); 
      response = Console.ReadLine(); 
     } 

Answer 2

do 
{ 
    // ... 

    Account asset = new Account(); 
    var accountList = new List<Account>(); 

    // ... 

    if (menuChoice == "3") 
    { 

     Console.WriteLine($"{asset.balance} is your asset, and {debt.balance} is your debt."); 
    } 
} while (/* ... */); 

你宣佈一個新的assset對象和每個菜單循環的accountList。當然，當您打印時，assset.balance將爲零，因爲當您選擇菜單選項＃3時它總是一個新的新對象。

你應該將列表中的菜單循環之外：

static void Main(string[] args) 
{ 
    string menuChoice; 
    string response; 
    var accountList = new List<Account>(); 

    do { // ... 

;創建內部菜單選項＃1 Account一個新實例：

if (menuChoice == "1") 
    { 
     do 
     { //D1 
      var asset = new Account(); 
      // ... rest of your code 
     } while (response != "n"); 
    } 

---

至於計算資產和債務，你需要分別找到正數或負數的所有帳戶：

var assets = accountList.Where(x => x.balance > 0).Sum(x => x.balance); 
// assuming that you used negative value for debt 
var debts = accountList.Where(x => x.balance < 0).Sum(x => x.balance); 

理想情況下，你會想要兩個不同類型的Account少亂碼：

public abstract class Account 
{ 
    public string Name { get; set; } 
    public decimal Balance { get; set; } 
} 

public class Asset : Account { } 
public class Debt : Account { } 

// in option #3 
accountList.OfType<Asset>().Sum(x => x.Balance); 

Answer 3

的一個問題是完全按照你所描述的，因爲你在每次循環創建的accountList一個新實例它丟失了上次的信息。如下所示將它移到循環外部。

我想你可以使用Dictionary<string, decimal>如果你想。好處是它不允許重複鍵，並允許您通過鍵訪問值。如果你不需要這些東西，那麼List<T>就像現在一樣好。

有其他一些問題，所以我已經採取了一些調戲你的代碼，但我相信下面的你想要做什麼：

void Main() 
{ 
    string menuChoice; 
    string response; 
    var accountList = new List<Account>(); 
    var debtList = new List<Debt>(); 

    do 
    { 
     response = ""; 
     Console.WriteLine("\nWelcome to your Net Worth Calculator.\n \n MENU:\n 1. Add Asset\n 2. Add Debt\n 3. View Summary\n 4. Quit"); 
     Console.WriteLine(" "); 
     Console.WriteLine("What would you like to do?\nPlease make a selection: "); 

     menuChoice = Console.ReadLine(); 

     if (menuChoice == "1") 
     { 
      do 
      { 
       Account asset = new Account(); 

       Console.WriteLine("\nGreat! Let's add an account."); 
       Console.WriteLine("Account name:"); 
       asset.name = Console.ReadLine(); 
       Console.WriteLine("Your account name is: " + asset.name); 

       Console.WriteLine("\nWhat is your current account balance with " + asset.name + "?"); 
       Console.WriteLine("Balance:"); 
       asset.balance = Decimal.Parse(Console.ReadLine()); 

       accountList.Add(asset); 

       Console.WriteLine("Your balance with " + asset.name + " is currently $" + asset.balance + "."); 

       Console.WriteLine("\n\nWould you like to add another account? y/n"); 
       response = Console.ReadLine(); 
      } while (response != "n"); 
     } 

     if (menuChoice == "2") 
     { 
      do 
      { 
       Debt debt = new Debt(); 

       Console.WriteLine("\nGreat! Let's add a debt."); 
       Console.WriteLine("Debt name:"); 
       debt.name = Console.ReadLine(); 
       Console.WriteLine("Your debt name is: " + debt.name); 

       Console.WriteLine("\nWhat is your current debt balance with " + debt.name + "?"); 
       Console.WriteLine("Balance:"); 
       debt.balance = Decimal.Parse(Console.ReadLine()); 

       debtList.Add(debt); 

       Console.WriteLine("Your balance with " + debt.name + " is currently $" + debt.balance + "."); 

       Console.WriteLine("\n\nWould you like to add another debt? y/n"); 
       response = Console.ReadLine(); 
      } while (response != "n"); 
     } 

     if (menuChoice == "3") 
     { 
      var totalAsset = accountList.Sum(x => x.balance); 
      var totalDebt = debtList.Sum(x => x.balance); 

      Console.WriteLine("Let's take a look at the accounts and balances that you've added so far:"); 
      Console.WriteLine($"{totalAsset} is your asset, and {totalDebt} is your debt."); 
      decimal netWorth = totalAsset - totalDebt; 
      Console.WriteLine($"Net worth: {netWorth}"); 

      Console.WriteLine("\n\nPress any key to return to the menu"); 
      Console.ReadLine(); 
     } 
    } while (menuChoice != "4"); 
} 

public class Account 
{ 
    public string name {get;set;} 
    public decimal balance {get;set;} 
} 

public class Debt 
{ 
    public string name {get;set;} 
    public decimal balance {get;set;} 
} 

摘要：

• 感動accountList外循環所以它不會在下一次迭代中被刪除
• 添加debtList追蹤債務（假設您有這個但沒有顯示它？）
• 的菜單選項2新增部分（再次假設你只是錯過了嗎？）
• 在菜單選項更改了3個邏輯顯示總計正確
• 新增邏輯菜單選項4（退出）選擇何時退出

根據共同的帳戶/債務份額，您可能只能擁有一個班級而不是兩個班級。