我正在自己学习C＃并且坚持练习。我需要确保没有重复的OrderNumbers输入到我的订单数组中。我认为练习的想法是使用Equals（）然而，我无法弄清楚如何让它工作。我还没有学到任何太过花哨的东西。 Equals（）会比使用方法更好吗？此外，我不知道如何调用该方法，所以我看到了真值或假值。如果找到重复，则应循环并要求用户重新输入。因为我真的很沮丧，所以提前感谢你...我需要一位导师！
class Program
{
static void Main()
{
Order[] order = new Order[3];
int orderNumber; // hold temp value until object is created
string customerName;
int qtyOrdered;
for (int x = 0; x < order.Length; ++x) //to fill array
{
Console.Write("Enter Order Number: ");
int.TryParse(Console.ReadLine(), out orderNumber); // put order number in temp
if (order[x] != null)
{
if (IsOrderNumberInUse(orderNumber, order) == true)
{
Console.WriteLine("Duplicate order number");
}
}
GetData(out customerName, out qtyOrdered);
order[x] = new Order(orderNumber, customerName, qtyOrdered);
}
Console.ReadLine();
}
//METHOD TO CHECK FOR DUPLICATES
private static bool IsOrderNumberInUse(int orderNumber, Order[] orders)
{
foreach (Order order in orders)
{
if (order.OrderNumber == orderNumber)
{
return true;
}
}
// If orderNumber was not found
return false;
}
static void GetData(out string customerName, out int qtyOrdered)
{
//Console.Write("Enter Order Number: ");
//int.TryParse(Console.ReadLine(), out orderNumber);
Console.Write("Enter Customer Name: ");
customerName = Console.ReadLine();
Console.Write("Enter Quantity Ordered: ");
int.TryParse(Console.ReadLine(), out qtyOrdered);
}
class Order
{
private const double PRICE = 19.95;
public int OrderNumber { get; set; }
public string CustomerName { get; set; }
public int QtyOrdered { get; set; }
public double totalPrice
{
get
{
return QtyOrdered * PRICE;
}
}
public Order(int orderNumber, string customer, int qty) // Constructor
{
OrderNumber = orderNumber;
CustomerName = customer;
QtyOrdered = qty;
}
public override string ToString()
{
return ("\n" + GetType() + "\nCustomer: " + CustomerName + "\nOrder Number: " + OrderNumber +
"\nQuantity: " + QtyOrdered + "\nTotal Order: " + totalPrice.ToString("C2"));
}
public override bool Equals(object x)
{
bool isEqual;
if (this.GetType() != x.GetType())
isEqual = false;
else
{
Order temp = (Order)x;
if (OrderNumber == temp.OrderNumber)
isEqual = true;
else
isEqual = false;
}
return isEqual;
}
public override int GetHashCode()
{
return OrderNumber;
}
}
}
我正在尝试不使用列表，因为我已经学会了它，而我接下来的两个练习与此相关。我担心如果使用列表，我会更加迷失。我得到null错误，需要帮助修复它们。这是我的代码。使用Equals会比我目前正在努力的方法更好吗？感谢您的耐心......
class Program
{
static void Main()
{
Order [] orders = new Order [3];
int tempOrderNumber;
string tempCustomerName;
int tempQtyOrdered;
for (int x = 0; x < orders.Length; ++x) // fill list
{
tempOrderNumber = AskForOrderNumber(orders);
GetData(out tempCustomerName, out tempQtyOrdered);
orders[x] = new Order(tempOrderNumber, tempCustomerName, tempQtyOrdered);
}
Console.ReadLine();
}
private static int AskForOrderNumber(Order [] orders)
{
int tempOrderNumber;
Console.Write("Enter Order Number: ");
int.TryParse(Console.ReadLine(), out tempOrderNumber);
if (orders[0] !=null && IsOrderNumberInUse(tempOrderNumber, orders) == true) //Check for duplicates
{
Console.WriteLine("Duplicate order number");
AskForOrderNumber(orders);
}
return tempOrderNumber;
}
static void GetData(out string tempCustomerName, out int tempQtyOrdered)
{
Console.Write("Enter Customer Name: ");
tempCustomerName = Console.ReadLine();
Console.Write("Enter Quantity Ordered: ");
int.TryParse(Console.ReadLine(), out tempQtyOrdered);
}
private static bool IsOrderNumberInUse(int tempOrderNumber, Order[] orders)
{
foreach (Order order in orders)
{
if (order.OrderNumber == tempOrderNumber)
{
return true;
}
}
return false;
}
class Order
{
private const double PRICE = 19.95;
public int OrderNumber { get; set; }
public string CustomerName { get; set; }
public int QtyOrdered { get; set; }
public double totalPrice
{
get
{
return QtyOrdered * PRICE;
}
}
public override string ToString()
{
return ("\n" + GetType() + "\nCustomer: " + CustomerName + "\nOrder Number: " + OrderNumber +
"\nQuantity: " + QtyOrdered + "\nTotal Order: " + totalPrice.ToString("C2"));
}
public Order(int orderNumber, string customerName, int qtyOrdered)
{
OrderNumber = orderNumber;
CustomerName = customerName;
QtyOrdered = qtyOrdered;
}
public override bool Equals(Object x)
{
bool isEqual;
if(this.GetType() != x.GetType())
isEqual = false;
else
{
Order temp = (Order) x;
if(OrderNumber == temp.OrderNumber)
isEqual = true;
else
isEqual = false;
}
return isEqual;
}
public override int GetHashCode()
{
return OrderNumber;
}
}
}
答案 0 :(得分：1)
为了解决您的问题，我建议您使用List<Order>，因为列表可以调整大小我相信它们将是更好的选择。
您当前的方法不起作用，因为您在 之后才创建 使用列表/固定代码 你应该使用临时 如果输入无效，则再次询问用户 上面的示例显示了我修复问题并使用 检查验证的更好方法 您当前检查重复项的方法也没有任何问题，但可以使用LINQ进行改进。 （order[x]。
orderNumber，但是因为数组是空的，你也可以在第一次检查时得到空错误（可以修复），因此我会再次推荐一个List List<Order> orders = new List<Order>(); //Orders list
int orderNumber; //Temporary order number
string customerName; //Temporary customer name
int qtyOrdered; //Temporary quantity
for (int x = 0; x < 3; ++x) //Fill List
{
Console.Write("Enter Order Number: ");
int.TryParse(Console.ReadLine(), out orderNumber); //Parse order number
if (IsOrderNumberInUse(orderNumber, orders) == true) //Check for duplicates
{
Console.WriteLine("Duplicate order number");
}
//Get data and add to list
GetData(out customerName, out qtyOrdered);
orders.Add(new Order(orderNumber, customerName, qtyOrdered));
}
Console.ReadLine();
List的建议，但是如果您想进一步提示用户重新输入它的值正在使用中。您可以通过创建一个方法来询问用户输入，并通过递归，再次询问它们是否正在使用。...
for (int x = 0; x < 3; ++x) //Fill List
{
orderNumber = AskForOrderNumber(orders);
//Get data and add to list
GetData(out customerName, out qtyOrdered);
orders.Add(new Order(orderNumber, customerName, qtyOrdered));
}
Console.ReadLine();
}
private static int AskForOrderNumber(List<Order> orders)
{
int orderNumber;
Console.Write("Enter Order Number: ");
int.TryParse(Console.ReadLine(), out orderNumber); //Parse order number
if (IsOrderNumberInUse(orderNumber, orders) == true) //Check for duplicates
{
Console.WriteLine("Duplicate order number");
AskForOrderNumber(orders);
}
return orderNumber;
}
using System.LINQ）private static bool IsOrderNumberInUse(int orderNumber, List<Order> orders)
{
return orders.Any(o => o.OrderNumber == orderNumber);
}