您将如何重构具有多个 bool 字段的代码？

Question

例如，我有几种可能的逻辑组合，我需要确定哪些是正确的并根据结果执行操作。

public bool VerificationConnection(Transport objectFirst, Transport objectSecond) 
{
   bool isCarFirst = objectFirst is Car;
   bool isMotorcycleFirst = objectFirst is Motorcycle;
   
   bool isCarSecond = objectSecond is Car;
   bool isMotocycleSecond = objectSecond is Motorcycle;

   if(isCarFirst && isCarSecond) 
   {
      //do something
   }
   if(isCarFirst && isMotocycleSecond) 
   {
     //do something
   }
   if(isMotocycleFirst && isCarSecond) 
   {
     //do something
   }

   return true;
}

Answer 1

您可以使用派遣 table。对于具有两个布尔字段的用例，委托字典或类似的东西可能就足够了。

Dictionary<(bool, bool), Delegate> dispatch = new Dictionary<(bool, bool), Delegate>();

dispatch[(true, true)] = new Action(() => Console.WriteLine("Hello"));
dispatch[(true, false)] = new Action<string>(s => Console.WriteLine(s));

dispatch[(true, true)].DynamicInvoke();
dispatch[(true, false)].DynamicInvoke("World");

Answer 2

您可以在 switch 语句中使用方便的 pattern matching (C# 7.0 - C# 10.0)。这将两种类型模式组合成一个元组模式：

switch ((objectFirst, objectSecond)) {
    case (Car, Car):
        DoSomething();
        break;
    case (Car, Motorcycle):
        DoSomething();
        break;
    case (Motorcycle, Car):
        DoSomething();
        break;
    case (Motorcycle, Motorcycle):
        DoSomething();
        break;
}

如果你需要强类型的值，你可以使用声明模式；但是，这也可能是一个提示，您的代码没有最佳地使用面向对象的原则。

switch ((objectFirst, objectSecond)) {
    case (Car c1, Car c2):
        DoSomething(c1, c2);
        break;
    case (Car c, Motorcycle m):
        DoSomething(c, m);
        break;
    case (Motorcycle m, Car c):
        DoSomething(m, c);
        break;
    case (Motorcycle m1, Motorcycle m2):
        DoSomething(m1, m2);
        break;
}

如果 switch 语句 returns 一个值，则使用 switch expression 代替。

var value = (objectFirst, objectSecond) switch {
    (Car c1, Car c2) => GetValue(c1, c2),
    (Car c, Motorcycle m) => GetValue(c, m),
    (Motorcycle m, Car c) => GetValue(m, c),
    (Motorcycle m1, Motorcycle m2) => GetValue(m1, m2),
    _ => null
};

您将如何重构具有多个 bool 字段的代码？

How would you refactor code with many bool fields?

c#

refactoring