C# 如何从Xamarin中的选取器长度计算值

我的目的是在xamarin上创建长度转换器。我创建了picker函数，以便用户可以选择需要转换的长度

但对于下一步，我不知道如何创建一个方法，该方法可以处理和设置每个长度和倍数的值以及提示表单用户的值

有人能帮我用这个方法吗

namespace LengthConversion
{
   public class PickerLength 
    {
        public int rate = 0;


        public List<Length> LengthList { get; set; }

        public PickerLength()
        {
            LengthList = GetLength().OrderBy(t => t.Value).ToList();
        }

        public List<Length> GetLength()
        {
            var length = new List<Length>()
            {
                new Length() {Key = 1, Value="Millimetres(mm)"},
                new Length() {Key = 2, Value="Centimetre(cm)"},
                new Length() {Key = 3, Value="Meters(m)"},
                new Length() {Key = 4, Value="Kilometers(km)"},
                new Length() {Key = 5, Value="Feet(ft)"},
                new Length() {Key = 6, Value="Inches(in)"},
                new Length() {Key = 7, Value="Decimeter"},
                new Length() {Key = 8, Value="Mile(m)"},
                new Length() {Key = 9, Value="Yerd"},
                new Length() {Key = 10, Value="Furlong"},
                new Length() {Key = 11, Value="Hand(horses)"},
                new Length() {Key = 12, Value="Fathom"}
            };


            return length;
        }


    }


    public class Length
    {
        public int Key { get; set; }
        public string Value { get; set; }
    }

}

---

这可以通过选择参考测量单位来实现，如

米
。然后存储所有其他度量单位的系数。然后将每个输入转换为参考度量单位，最后转换为目标度量单位

这不是实现这一点的唯一方法，也不是生产准备好的样品

例如：

private readonly UnitOfMeatures _referenceUnits = UnitOfMeasures.Meter;

// Multiply the input values by these to get to the reference units.
// Divide the reference values by these to get to the output units.
private const double COEFFICIENT_METER = 1.0f; 
private const double COEFFICIENT_KILOMETER = 1000.0f;    
private const double COEFFICIENT_FOOT = 0.3048f;    
private const double COEFFICIENT_INCH = 0.0254f;         // use Google to find these.

// Create map of UnitOfMeasures to coefficients
private Dictionary<UnitOfMeasures, double> _coefficientMap = new Dictionary<UnitOfMeasures, double>() {
    {UnitOfMeasures.Meter, COEFFICIENT_METER}, {UnitOfMeasure.Kilometer, COEFFICIENT_KILOMETER} // etc...
};

public double ConvertUnits(UnitOfMeasures inputUnits, double value, UnitOfMeasures outputUnits) {
    double result = 0.0f;

    // convert to reference units
    result = value * _coefficientMap[inputUnits];

    // convert to output units
    result = result / _coefficientMap[outputUnits];

    return result;
}

private readonly UnitOfMeasures\u referenceUnits=UnitOfMeasures.Meter；
//将输入值乘以这些值，得到参考单位。
//将参考值除以这些值，得到输出单位。
私人常数双系数表=1.0f；
私人建筑双系数_千米=1000.0f；
私人建筑双系数_FOOT=0.3048f；
私人建筑双系数_英寸=0.0254f；//使用谷歌查找这些。
//创建测量单位到系数的映射
私有字典_coefficientMap=新字典（）{
{计量单位.米，系数{米}，{计量单位.公里，系数{公里}//等等。。。
};
公共双转换器单位（测量单位输入单位、双值、测量单位输出单位）{
双结果=0.0f；
//转换为参考单位
结果=值*_系数映射[输入单位]；
//转换为输出单位
结果=结果/_系数映射[输出单位]；
返回结果；
}

namespace LengthConversion
{

    [XamlCompilation(XamlCompilationOptions.Compile)]

    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();
            BindingContext = new PickerLength();
        }
    }
}

private readonly UnitOfMeatures _referenceUnits = UnitOfMeasures.Meter;

// Multiply the input values by these to get to the reference units.
// Divide the reference values by these to get to the output units.
private const double COEFFICIENT_METER = 1.0f; 
private const double COEFFICIENT_KILOMETER = 1000.0f;    
private const double COEFFICIENT_FOOT = 0.3048f;    
private const double COEFFICIENT_INCH = 0.0254f;         // use Google to find these.

// Create map of UnitOfMeasures to coefficients
private Dictionary<UnitOfMeasures, double> _coefficientMap = new Dictionary<UnitOfMeasures, double>() {
    {UnitOfMeasures.Meter, COEFFICIENT_METER}, {UnitOfMeasure.Kilometer, COEFFICIENT_KILOMETER} // etc...
};

public double ConvertUnits(UnitOfMeasures inputUnits, double value, UnitOfMeasures outputUnits) {
    double result = 0.0f;

    // convert to reference units
    result = value * _coefficientMap[inputUnits];

    // convert to output units
    result = result / _coefficientMap[outputUnits];

    return result;
}