c# - 更新我的货币转换器 c# 中的汇率

Question

我只是想知道如何在整个程序中使用更新后的汇率。这是迄今为止我的代码供引用...

//Form 1
private void update_Click(object sender, EventArgs e)
{
    if (fromcountry.Text == tocountry.Text)
    { 
        MessageBox.Show(" Please Choose Two Different Currencies To Use This Function", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
    }
    else
    {
        btnconvert.Enabled = true;
        Exchange_Rate frm = new Exchange_Rate();
        frm.Show(this);
    }
}
//Form 1 one of the comboboxes for selecting 2nd country
private void tocountry_SelectedIndexChanged(object sender, EventArgs e)
{
    btnupdate.Enabled = true;
    btnconvert.Enabled = true;
    txtvalue.Enabled = true;
    exchange();
}
private void exchange()
{
    if (fromcountry.Text == tocountry.Text)
    {
        lblexchange.Text = "1";
    }
    else if (fromcountry.Text == "SGD - Singapore Dollar" && tocountry.Text == "USD - US Dollar")
    {
        lblexchange.Text = "1.26";
    }
    else if (fromcountry.Text == "SGD - Singapore Dollar" && tocountry.Text == "MYR - Malaysian Ringgit")
    {
        lblexchange.Text = "2.35";
    }
    else if (fromcountry.Text == "SGD - Singapore Dollar" && tocountry.Text == "EUR - Euro")
    {
        lblexchange.Text = "0.60";
    }
//Form 2
private void btnok_Click(object sender, EventArgs e)
{
    try
    {
        double exchange;
        exchange = Double.Parse(txtcurrent.Text);
        var frm = (currencyconverter)this.Owner;
        frm.PassValue(txtcurrent.Text);
        this.Close();
    }
    catch
    {
        MessageBox.Show("Please Enter Numbers", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
        txtcurrent.Text = "";
    }
}

我知道使用 if-else 方法在程序开始时获得费率太模糊，而且我只是一个学习简单编程的学生。但我仍然需要知道当我再次按下相同的转换时如何使用更新的汇率。如果没有足够的信息，我可以帮助您获得更多编码

Answer 1

您可以使用共享货币对象来保存有关货币汇率的信息

public class Currency
{
  private Currency(string name)
  {
    Name = name;
  }

  public string Name {get; private set;}
  public decimal Rate {get; private set;}

  private void SetRate(decimal rate)
  {
    Rate = rate;
    OnRateChanged(this);
  }

  public static event EventHandler RateCanged;
  private static OnRateChanged(Currency currency)
  {
    var handler = RateChanged;
    if(handler != null)
    {
      handler(currency, EventArgs.Empty);
    }
  }

  private Dictionary<string, Currency> currencies = new Dictionary<string, Currency>();

  public static Currency GetCurrency(string name)
  {
    Currency currency;
    if(!currencies.TryGetValue(name, out currency))
    {
      currency = new Currency(name);
      currencies[name] = currency;
    } 
  }
}

所以您有一个简单的共享费率存储空间，您可以在任何地方使用它

class Form1
{
  public Form1()
  {
    ...
    Currency.RateChanged += RateChanged;
  }

  private void RateChanged(object source, EventArgs e)
  {
    labelRate.Text = Currency.GetCurrency("USD").Rate;
  }
}

class Form2
{
  public Form2()
  {
    ...
    rateTextBox.Text = Currency.GetCurrency("USD").Rate.ToString();
  }

  void updateButtin_Click()
  {
    Currency.GetCurrency("USD").SetRate(decimal.Parse(rateTextBox.Rate));
  }  
}