Question

您好我真的需要这个继承项目的帮助。当用户在组合框中选择一个值时，我需要我的表单来显示每个标签中的所有数据。我得到了列表中声明的所有数据，但我不知道为什么当我选择值时标签仍显示ZERO。

 public partial class Form1 : Form
{


    public Form1()
    {

        InitializeComponent();

    }

    private void accountNumComboBox_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (accountNumComboBox.SelectedIndex == 0)
        {
            SavingsAccount savings = new SavingsAccount();
            ownerIdLabel.Text = savings.OwnerId;
            balanceLabel.Text = savings.Balance.ToString("c");
            interestLabel.Text = (string.Format("{0}%", savings.Interest));
        }
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        List<SavingsAccount> savings = new List<SavingsAccount>();

        SavingsAccount savings1 = new SavingsAccount();
        savings1.OwnerId = "0001";
        savings1.AccountNumber = "31-1000";
        savings1.Balance = 100m;
        savings1.Interest = 0.01;

        SavingsAccount savings2 = new SavingsAccount();
        savings2.OwnerId = "0002";
        savings2.AccountNumber = "31-1001";
        savings2.Balance = 1000m;
        savings2.Interest = 0.0125;

这是我的SavingsAccount类

 class SavingsAccount : BankAccount
{
    //field
    private double _interest;

    //constructor
    public SavingsAccount(string ownerID, string acctNumber, decimal balance, double interest)
        : base(ownerID, acctNumber, balance)
    {
        _interest = interest;
    }
    //interest property
    public double Interest
    {
        get { return _interest; }
        set { _interest = value; }
    }
    public SavingsAccount()
    {

    }
}

我很感激你的帮助。谢谢！

Answer 1

虽然您在下面的代码中声明了值，但您实际上并没有使用它。

 private void Form1_Load(object sender, EventArgs e)
{
    List<SavingsAccount> savings = new List<SavingsAccount>();

    SavingsAccount savings1 = new SavingsAccount();
    savings1.OwnerId = "0001";
    savings1.AccountNumber = "31-1000";

当您编写下面的代码时，您将在事件内部创建一个新的本地化对象;您之前没有使用过您尝试过的值：

 private void accountNumComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
    if (accountNumComboBox.SelectedIndex == 0)
    {
        SavingsAccount savings = new SavingsAccount();
        ownerIdLabel.Text = savings.OwnerId;
        balanceLabel.Text = savings.Balance.ToString("c");

我的建议是移动这段代码：List<SavingsAccount> savings = new List<SavingsAccount>();就在private double _interest声明的下方。这将使您可以通过其他方法和事件访问它。

C＃为什么不显示我在List中设置的值？

1 个答案: