C#的新手,今天我已经在这里发布了一次,我感谢所有的帮助!我有一个我在Visual Basic中创建的程序.窗体有一个主表-的AccountForm.cs,三道关拍表格- WithdrawlForm.cs,DepositForm.cs和InterestForm.cs.我有两个类,Account.cs及其派生类SavingsAccount.cs.我试图将InterestRate下面的字符串更改为用户输入的利率InterestForm.此代码位于SavingsAccount类.cs文件中.
public new string toString()
{
return String.Format("Account Number: {0} Balance: {1:C} Interest Rate: {2:P}", AccountNumber, AccountBalance, InterestRate);
}
完整的SavingsAccount.cs文件
namespace Assignment_6_third_attempt
{
public class SavingsAccount : Account
{
private InterestForm interestForm = new InterestForm();
private double interestRate = 0.0;
#region Constructors
public SavingsAccount(int accountNumber)
{
base.accountNumber = accountNumber;
}
public SavingsAccount() { }
#endregion
double InterestRate
{
get { return interestForm.interestRate ; }
set { interestRate = interestForm.interestRate; }
}
public double Interest(double amount)
{
InterestRate = interestForm.interestRate;
return InterestRate;
}
public void AddInterest(double amount)
{
//interestForm.CalculateInterest();
AccountBalance = amount;
}
public new string toString()
{
return String.Format("Account Number: {0} Balance: {1:C} Interest Rate: {2:P}", AccountNumber, AccountBalance, InterestRate);
}
}
}
这是我的AccountForm.cs文件(此表格是主表格,其中显示了帐号,帐户余额和利率.
namespace Assignment_6_third_attempt
{
public partial class AccountForm : Form
{
SavingsAccount savingsAccount;
public System.Windows.Forms.Label labelInformation;
public AccountForm()
{
InitializeComponent();
labelInformation = accountInfoLabel;
}
private void createAccountButton_Click(object sender, EventArgs e)
{
Random random = new Random();
int newAccountNumber = random.Next(0, 1000000);
savingsAccount = new SavingsAccount(newAccountNumber);
MessageBox.Show(savingsAccount.toString());
accountInfoLabel.Text = savingsAccount.toString();
depositButton.Enabled = true;
withdrawalButton.Enabled = true;
interestButton.Enabled = true;
}
private void depositButton_Click(object sender, EventArgs e)
{
DepositForm depForm = new DepositForm();
depForm.ShowDialog();
savingsAccount.Deposit((double)depForm.DepositAmount);
accountInfoLabel.Text = savingsAccount.toString();
}
private void withdrawalButton_Click(object sender, EventArgs e)
{
try
{
WithdrawalForm withdrawForm = new WithdrawalForm();
withdrawForm.ShowDialog();
savingsAccount.Withdraw((double)withdrawForm.WithdrawAmount);
accountInfoLabel.Text = savingsAccount.toString();
}
catch (InvalidOperationException ex)
{
MessageBox.Show(ex.Message);
}
}
private void closeAccountButton_Click(object sender, EventArgs e)
{
depositButton.Enabled = false;
withdrawalButton.Enabled = false;
accountInfoLabel.Text = "";
savingsAccount = null; //this will clean it up off the heap.
}
private void interestButton_Click(object sender, EventArgs e)
{
InterestForm interestForm = new InterestForm(savingsAccount.AccountBalance);
interestForm.ShowDialog();
savingsAccount.AddInterest(interestForm.CalculateInterest());
accountInfoLabel.Text = savingsAccount.toString();
savingsAccount.Interest(interestForm.interestRate);
accountInfoLabel.Text = savingsAccount.toString();
}
}
}
最后,这是我的InterestForm.cs代码,用户可以在NumericUpDown控件中输入术语和速率.
namespace Assignment_6_third_attempt
{
public partial class InterestForm : Form
{
private Account account = new Account();
//private double accountBalance;
public double interestRate = 0.0;
public InterestForm()
{
InitializeComponent();
}
public InterestForm(double accountBalance) : this()
{
//InitializeComponent();
account.AccountBalance = accountBalance;
}
private void addInterestButton_Click(object sender, EventArgs e)
{
double interestRate = double.Parse(interestUpDown.Text);
CalculateInterest();
this.Close();
}
public double CalculateInterest()
{
//A = P(1 + rt)
double accountBalance = account.AccountBalance;
double interestRate = (double)interestUpDown.Value;
double term = (double)termUpDown.Value;
double estimateInterest = (accountBalance * (1 + (interestRate * term)));
return estimateInterest;
}
}
}
编辑:
除了提到的所有原始问题之外,您似乎在这里将您的interestRate private 字段范围与interestRate 局部变量混淆:
private void addInterestButton_Click(object sender, EventArgs e)
{
double interestRate = double.Parse(interestUpDown.Text); //this is local variable!!
CalculateInterest();
this.Close();
}
请注意,您使用的是本地 interestRate,而不是您的班级interestRate.同样,要小心变量的范围.无法全局访问局部变量,如果在本地方法中具有相同的变量名,则必须将其与使用this关键字的全局变量(类'字段)区分开来(this.VariableName字段VariableName是本地的).
在上面的例子中,只需使用class字段interestRate而不是定义新的局部变量interestRate:
private void addInterestButton_Click(object sender, EventArgs e)
{
interestRate = double.Parse(interestUpDown.Text); //remove the double
CalculateInterest();
this.Close();
}
原版的:
该setter和getter的InterestRate似乎... 不对称:
double InterestRate
{
get { return interestForm.interestRate ; } //you get from other form
set { interestRate = interestForm.interestRate; } //and you set from other form
}
你interestForm.interestRate从其他形式获得并将其设置为interestRate你的Form但你从不使用本地interestRate.将其改为:
double InterestRate
{
get { return interestRate ; }
set { interestRate = value; }
}
你的情况也是如此Interest:
public double Interest(double amount)
{
InterestRate = interestForm.interestRate;
return InterestRate;
}
你再次使用你的私人Form,除了被构建之外,在课堂上没用.使用你的amount代替:
public double Interest(double amount)
{
InterestRate = amount; //change into this
return InterestRate;
}
现在,请注意:
private void interestButton_Click(object sender, EventArgs e)
{
InterestForm interestForm = new InterestForm(savingsAccount.AccountBalance);
interestForm.ShowDialog();
savingsAccount.AddInterest(interestForm.CalculateInterest());
accountInfoLabel.Text = savingsAccount.toString();
savingsAccount.Interest(interestForm.interestRate);
accountInfoLabel.Text = savingsAccount.toString();
}
你已经InterestForm宣布了,但它是一个new InterestForm,它不是你private InterestForm的SavingAccount.简而言之,虽然它们共享相同的名称,但InterestForm您声明并且InterestForm在您SavingAccount的两个不同的表单实例中interestForm.查看访问修饰符 - 而不是实例的名称 - 以了解您的范围object.
话虽如此,上面的设计使用非字段InterestForm来填补你的兴趣是可以的.我甚至会说,InterestForm不需要使用私人.你只需要外部的值传递InterestForm有你的SavingAccount实例,而不是创建私有InterestForm你SavingAccount