C# 函数和条件运算符

Question

Duplicate

我能做到:

Func<CategorySummary, decimal> orderByFunc;
if (orderBy == OrderProductsByProperty.Speed)
     orderByFunc = x => x.Speed;
else
    orderByFunc = x => x.Price;

为什么我不能这样做:

Func<CategorySummary, decimal> orderByFunc = (orderBy == OrderProductsByProperty.Speed) ? x => x.Speed : x => x.Price;

Answer 1

条件运算符上的“类型推断”不够好，我收到一条消息

Type of conditional expression cannot be determined because there is no implicit conversion between 'lambda expression' and 'lambda expression'

你总是可以在右侧显式显示，a la

var o = true ? new Func<int,int>(x => 0) : new Func<int,int>(x => 1);

无论如何，关于 lambda 的类型、类型推断和条件运算符如何交互，这只是一个小麻烦。