具有可能的循环依赖关系的测量单元的枚举

Question

我有一些定义测量信息的枚举，如体积、质量、距离等.

它们的定义如下：

/// <summary>
/// Units for measurement of area.
/// </summary>
public enum Area
{
    /// <summary>
    /// Meters squared.
    /// </summary>
    M2 = 0,
    /// <summary>
    /// Feet squared.
    /// </summary>
    FT2
}

我有必要显示一个简短和长的描述单位。在我的例子中，对仪表的简短描述将是[m]，而long将简单地称为Meters。还有其他更大的枚举，用于定义Kilometers per hour per second/[km/h/s]的加速。

到目前为止，我所做的是使用DescriptionAttribute属性来提供简短的描述：

/// <summary>
/// Distance measurement units
/// </summary>
public enum Distance
{
    /// <summary> 
    /// Meters.
    ///</summary> 
    [Description("[m]")]
    M = 0,        
    ...
}

这已经适用于有一种Distance类型的东西。现在我得到了定义为整数类型的东西，它们实际上是一种距离度量：

public class MovementSnapshot
{
    /// <summary>
    /// The total distance traveled, in meters.
    /// </summary>
    public int TotalTravelDistance { get; private set; }

    /// <summary>
    /// The current speed of the car. In KM/H
    /// </summary>
    public int Speed { get; private set; }

    /// <summary>
    /// The maximum speed achieved. In KM/H
    /// </summary>
    public int MaxSpeed { get; private set; }
}

我定义了一个自定义属性，以便在将这些属性输出到文件/屏幕等时更容易地显示这些属性。看起来是这样的：

/// <summary>
/// Provides an interface for the display of Unit-type objects
/// </summary>
public class UnitDisplayAttribute
    : Attribute
{
    /// <summary>
    /// The short display of the unit. Example: [N]
    /// </summary>
    public string ShortDisplay { get; private set; }

    /// <summary>
    /// Long long display of the unit. Example: Newtons
    /// </summary>
    public string LongDisplay { get; private set; }

    /// <summary>
    /// Construct the unit display attribute providing a short and long description of a unit type.
    /// </summary>
    /// <param name="longDisplay"></param>
    /// <param name="shortDisplay"></param>
    public UnitDisplayAttribute(string longDisplay, string shortDisplay)
    {
        this.ShortDisplay = shortDisplay;
        this.LongDisplay = longDisplay;
    }

}

这会很好，但是当我将属性应用到上面定义的类时，我会遇到这种情况：

public class MovementSnapshot
{
    /// <summary>
    /// The total distance traveled, in meters.
    /// </summary>
    [UnitDisplay("[m]", "Meters")]
    public int TotalTravelDistance { get; private set; }

    /// <summary>
    /// The current speed of the car. In KM/H
    /// </summary>
    [UnitDisplay("[km/h]", "Kilometers per hour")]
    public int Speed { get; private set; }

    /// <summary>
    /// The maximum speed achieved. In KM/H
    /// </summary>
    [UnitDisplay("[km/h]", "Kilometers per hour")]
    public int MaxSpeed { get; private set; }
}

我必须复制以相同单位测量的属性.有些课程有10-12个.然后，我考虑向UnitDisplayAttribute类添加一个构造函数，该类以Distance的一个实例为例，可以提供一个字符串方法来输出显示。

/// <summary>
/// Provides an interface for the display of Unit-type objects
/// </summary>
public class UnitDisplayAttribute
    : Attribute
{
    /// <summary>
    /// The short display of the unit. Example: [N]
    /// </summary>
    public string ShortDisplay { get; private set; }

    /// <summary>
    /// Long long display of the unit. Example: Newtons
    /// </summary>
    public string LongDisplay { get; private set; }

    public UnitDisplayAttribute(Distance d)
    {
        // check if the distance is meters, kilometers etc... and apply the appropriate short and long strings to the property.
    }

}

这对于上面的MovementSnapshot类很有效，但是将自定义属性应用到上面的Distance枚举会让人感到很尴尬，因为该属性接受相同类型的对象：

/// <summary>
/// Distance measurement units
/// </summary>
public enum Distance
{
    /// <summary> 
    /// Meters.
    ///</summary> 
    [UnitDisplay(Distance.M)]
    M = 0,        
    ...
}

我在这里什么都不担心吗？吉米在看这段代码时会失去理智吗？如何为表示为单元的对象和作为该单元的对象实现良好的显示？

Answer 1

我将提出一种完全不同的方法。我喜欢OOP。

创建一个界面。

public interface IUnitOfMeasure
{
    int Value { get; set; }
    string ShortDescription { get; }
    string LongDescription { get; }
}

和格式化器Enum

public enum UnitOfMeasureFormat { Short, Long }

然后实现了接口、过载和重载的ToString()方法。

public class Meters : IUnitOfMeasure
{
    public int Value { get; set; }
    public string ShortDescription { get { return "[m]"; }
    public string LongDescription { get { return "Meters"; }

    public override string ToString()
    {
        return this.Value + " " + this.ShortDescription;
    }

    public string ToString(UnitOfMeasureFormat format)
    {
        if (format == UnitOfMeasureFormat.Short)
        {
            return this.ToString();
        }

        return this.Value + " " + this.LongDescription;
    }
}

现在，您可以将类的属性设置为“更强”的类型。

public class MovementSnapshot
{
    public Meters TotalTravelDistance { get; private set; }

只需在需要显示ToString()方法时调用它。

myMovementSnapshot.TotalTravelDistance.ToString();

我在这里没有这样做，但是此时，您可能想开始考虑实现单元转换方法以及实现IEquatable和IComparable接口。