我工作的一个在线预订网站（航空公司），我想验证如果按照某些设置用户/客户的选择的路线是有效的。现有的codeS使用了大量的枚举，我发现自己做的很多，如果/当其它/别的一个特定的枚举映射到，我想发生特定动作。 我想要做的就是写一个枚举特定的方法，会做的映射我。有没有标准的方式来做到这一点？

I'm working on an online booking site (airline) and I want to validate if the user/customer's chosen route is valid according to some settings. The existing codes uses a lot of enums and I found myself doing lots of if/if else/else to map a specific enum to a particular action that I wanted to happen. What I want to do is to write a enum-specific method that would do the mapping for me. Is there any standard way to do this?

下面的的应用程序，code。使用相同的类名/枚举值等，从真正的应用程序的简化版本：

Here's a simplified version of the app code using the same class names/enum values etc from the real app:

// real app has 9 members, shortened for simplicity's sake
public enum RegionType
{
    Station,
    Country,
    All
}

public enum Directionality
{
    Between,
    From,
    To
}

// simplified version
public class Flight
{
     public RegionType RegionType { get; set; }
     public RegionType TravelRegionType { get; set; }
     public string RegionCode { get; set; }
     public string TravelRegionCode { get; set; }
     public string RegionCountryCode { get; set; }
     public string TravelRegionCountryCode { get; set; }
     public Directionality Directionality { get; set; }
}

下面是一些示例用法：

    // valid flight
    Flight flight = new Flight()
    {
        RegionCode = "NY",
        CountryCode = "JP",
        RegionType = RegionType.Station,
        TravelRegionType = RegionType.Country,
        Directionality = Directionality.Between
    };

    // these are the station code/country code that user selected
    // needs to be validated against the Flight object above
    var userSelectedRoutes = new List<KeyValuePair<string, string>>() 
    { 
        new KeyValuePair<string, string>("NY", "JP"),
        new KeyValuePair<string, string>("NY", "AU"),
        new KeyValuePair<string, string>("JP", "NY")
    };

有些code验证我写信，以减少嵌套的if / else的if / else枚举匹配：

Some code validation I wrote to lessen nested if/else if/else enum matching:

private bool IsRouteValid(Directionality direction, string origin, 
                          string destination, string departure, string arrival)
{
    // both departure station and arrival station
    if (direction == Directionality.Between)
    {
        return (origin.Equals(departure, StringComparison.OrdinalIgnoreCase) 
          && destination.Equals(arrival, StringComparison.OrdinalIgnoreCase)
               || origin.Equals(arrival, StringComparison.OrdinalIgnoreCase) 
          && destination.Equals(departure, StringComparison.OrdinalIgnoreCase));
    }
    else if (direction == Directionality.From)
    {
            return (origin.Equals(departure, 
                    StringComparison.OrdinalIgnoreCase));   
    }
    else if (direction == Directionality.To)
    {
            return (destination.Equals(arrival, 
                    StringComparison.OrdinalIgnoreCase));
    }

    return false;
}

和这里的杂乱code我想改变：

And here's the messy code I want to change:

if (flight.RegionType == RegionType.Station 
    && flight.TravelRegionType == RegionType.Country)
{
     return userSelectedRoutes.Any(route => 
            IsRouteValid(flight.Directionality, route.Key, route.Value,
            flight.RegionCode, flight.TravelRegionCode));
}
else if (flight.RegionType == RegionType.Country 
&& flight.TravelRegionType == RegionType.Station)
{
    return userSelectedRoutes.Any(route => 
           IsRouteValid(flight.Directionality, route.Key, route.Value,
           flight.CountryCode, flight.RegionCode));
}
else if (flight.RegionType == RegionType.Station 
&& flight.TravelRegionType == RegionType.Station)
{
    return userSelectedRoutes.Any(route => 
           IsRouteValid(flight.Directionality, route.Key, route.Value,
                       flight.RegionCode, flight.TravelRegionCode));
}
else if (flight.RegionType == RegionType.Station 
&& flight.TravelRegionType == RegionType.All)
{
    return userSelectedRoutes.Any(route => 
           IsRouteValid(flight.Directionality, route.Key, route.Value,
                       flight.RegionCode, route.Value));
}
else if (flight.RegionType == RegionType.All 
&& flight.TravelRegionType == RegionType.Station)
{
    return userSelectedRoutes.Any(route =>
           IsRouteValid(flight.Directionality, route.Key, route.Value,
           route.Key, flight.TravelRegionCode));
}
else if (flight.RegionType == RegionType.All 
        && flight.TravelRegionType == RegionType.All)
{
    return true;
}
else
{
    return false;
} 

注：

区域code =始发站/产地 TravelRegion code =到达站/目的地 在 =路线必须从给定始发站只有和到达站，反之亦然（例如NY-JP或JP-NY） 在 =从特定电台的任何途径（例如非盟的所有的） 到 =一个特定站点的任何途径（前的所有的-AU）

RegionCode = departure station/origin TravelRegionCode = arrival station/destination Between = routes must be only from the given departure station and arrival station and vice-versa (ex NY-JP or JP-NY) From = from particular station to any routes (ex AU-All) To = any routes to a particular station (ex All-AU)

如果你能注意到，在。任何上述所有条件相同略有改动。我想减少code冗余，如果可能的话。我用 KeyValuePair 所以我有两个出发站和到达站上的一种数据类型。

public enum MyEnum
{
    EnumValue1,
    EnumValue2,
    EnumValue3
}

private IDictionary<MyEnum, Action> Mapping = new Dictionary<MyEnum, Action>
    {
        { MyEnum.EnumValue1, () => { /* Action 1 */ } },
        { MyEnum.EnumValue2, () => { /* Action 2 */ } },
        { MyEnum.EnumValue3, () => { /* Action 3 */ } }
    };

public void HandleEnumValue(MyEnum enumValue)
{
    if (Mapping.ContainsKey(enumValue))
    {
        Mapping[enumValue]();
    }
}