单位转换器 C#

Question

单位转换器 C#

3

今天我没什么事情要做，所以决定尝试创建一个简单的单位转换器。目前为止，它运行良好，但由于我的使用了很多'if'语句，所以花费时间太长。我在网上搜索了在Visual Studio中制作的单位转换器的示例，但我找到的唯一一个是使用在线转换器进行计算的VS Basic货币转换器。那么有没有更快的方法来创建一个单位转换器呢？

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (listBox1.SelectedItem == listBox2.SelectedItem) 
        {
            txtAns.Text = txtFirstUnit.Text;
        }

        if (listBox1.SelectedItem == "Feet" && listBox2.SelectedItem == "Inches") 
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 12).ToString();
        }

        if (listBox1.SelectedItem == "Inches" && listBox2.SelectedItem == "Feet")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 12).ToString();
        }

        if (listBox1.SelectedItem == "Yard" && listBox2.SelectedItem == "Feet")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 3).ToString();
        }

        if (listBox1.SelectedItem == "Feet" && listBox2.SelectedItem == "Yard")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 3).ToString();
        }

        if (listBox1.SelectedItem == "Yard" && listBox2.SelectedItem == "Inches")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 36).ToString();
        }

        if (listBox1.SelectedItem == "Inches" && listBox2.SelectedItem == "Yard")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 36).ToString();
        }

        if (listBox1.SelectedItem == "Mile" && listBox2.SelectedItem == "Inches")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 63360).ToString();
        }

        if (listBox1.SelectedItem == "Inches" && listBox2.SelectedItem == "Mile")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 63360).ToString();
        }

        if (listBox1.SelectedItem == "Mile" && listBox2.SelectedItem == "Feet")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 5280).ToString();
        }

        if (listBox1.SelectedItem == "Feet" && listBox2.SelectedItem == "Mile")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 5280).ToString();
        }

        if (listBox1.SelectedItem == "Mile" && listBox2.SelectedItem == "Yard")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 1760).ToString();
        }

        if (listBox1.SelectedItem == "Yard" && listBox2.SelectedItem == "Mile")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 1760).ToString();
        }

        if (listBox1.SelectedItem == "Inches" && listBox2.SelectedItem == "Meters")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 39.370).ToString();
        }

        if (listBox1.SelectedItem == "Meters" && listBox2.SelectedItem == "Inches")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 39.370).ToString();
        }

        if (listBox1.SelectedItem == "Meters" && listBox2.SelectedItem == "Feet")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 3.2808).ToString();
        }

        if (listBox1.SelectedItem == "Feet" && listBox2.SelectedItem == "Meters")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 3.2808).ToString();
        }

        if (listBox1.SelectedItem == "Meters" && listBox2.SelectedItem == "Yard")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 1.0936).ToString();
        }

        if (listBox1.SelectedItem == "Yard" && listBox2.SelectedItem == "Meters")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 1.0936).ToString();
        }

        if (listBox1.SelectedItem == "Meters" && listBox2.SelectedItem == "Miles")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) * 0.00062137).ToString();
        }

        if (listBox1.SelectedItem == "Miles" && listBox2.SelectedItem == "Meters")
        {

            txtAns.Text = (double.Parse(txtFirstUnit.Text) / 0.00062137).ToString();
        }
    }
}

- pcnThird

2

有没有更快的方法来创建一个单位转换器？是的，它被称为查找表... - Mitch Wheat

2

我知道这不是一个生产系统，或者说不一定会发布给公众使用，但你一定要检查输入确保它们是合理的。 - Maurice Reeves

可能是如何在C#中创建通用的度量单位转换器？的重复问题。 - Sani Huttunen

1个回答

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可以查看英文原文，
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- agent-j · Answer 1

采用面向对象的方法可以消除 if (lst.SelectedItem) == 语句。

考虑下面这段代码，每个单元都有一个不同的类。没有找到 if 语句。

  public Form1()
  {
     InitializeComponent();

     fromList.Items.Add(new CentimeterFromMillimeterConverter());
     toList.Items.Add(new CentimeterToMillimeterConverter());
  }

  void Convert(double amount)
  {
     var from = (FromMillimeterConverter) fromList.SelectedItem;
     var to = (FromMillimeterConverter) toList.SelectedItem;
     to.Convert(from.Convert(amount));
  }

public abstract class ToMillimeterConverter
{
  public abstract double Convert(double unit);
  public override string ToString()
  {
     return GetType().Name.Replace("ToMillimeterConverter", "");
  }
}

public class CentimeterToMillimeterConverter : ToMillimeterConverter
{
  public override double Convert(double centimeters)
  {
     return 10 * centimeters;
  }
}

public abstract class FromMillimeterConverter
{
  public abstract double Convert(double unit);
  public override string ToString()
  {
     return GetType().Name.Replace("FromMillimeterConverter", "");
  }
}

public class CentimeterFromMillimeterConverter : FromMillimeterConverter
{
  public override double Convert(double centimeters)
  {
     return centimeters / 10;
  }
}