使用If扩展的代码中用了lambda表达式，如果前面的“p=>p.”能去掉的话，看起来就比较舒服了!编译器通过类型及上下文推演，应该可以做得到吧!
给出People类如下：
public static void Test1()
{
//常规代码
People people1 = new People { Name = "ldp615", IsHungry = true, IsThirsty = true, IsTired = true };
if (people1.IsHungry) people1.Eat();
if (people1.IsThirsty) people1.Drink();
if (people1.IsTired) people1.Rest();
people1.Work();
//使用扩展方法
People people2 = new People { Name = "ldp615", IsHungry = true, IsThirsty = true, IsTired = true }
.If(p => p.IsHungry, p => p.Eat())
.If(p => p.IsThirsty, p => p.Drink())
.If(p => p.IsTired, p => p.Rest());
people2.Work();
}
{
//常规代码
People people1 = new People { Name = "ldp615", IsHungry = true, IsThirsty = true, IsTired = true };
if (people1.IsHungry) people1.Eat();
if (people1.IsThirsty) people1.Drink();
if (people1.IsTired) people1.Rest();
people1.Work();
//使用扩展方法
People people2 = new People { Name = "ldp615", IsHungry = true, IsThirsty = true, IsTired = true }
.If(p => p.IsHungry, p => p.Eat())
.If(p => p.IsThirsty, p => p.Drink())
.If(p => p.IsTired, p => p.Rest());
people2.Work();
}
对引用类型我们可以使用Action，也以使用链式编程的方式将多个If串起来。
但对值类型来说，就要用Func了，每次返回一个新的值 ：
public static T If<T>(this T t, Predicate<T> predicate, Func<T, T> func) where T : struct
{
return predicate(t) ? func(t) : t;
}
{
return predicate(t) ? func(t) : t;
}
