我可以将lambda表达式数组传递给具有params参数的方法吗？ [英] Can I pass an array of lambda expressions to a method with a params argument?

问题描述

我想调用一个这样的方法：

I want to call a method like this:

签名： void方法（对象a，对象b，params LambdaExpression []表达式） ;

调用：方法（a，b，x => xA，x => xB） / code>

call: Method(a, b, x => x.A, x => x.B)

可以吗？

我们假设'x'的类型是一个恒定类型。例如，如果x => xA和y => yB是Funcs，则它们将是 Func< TType，*> ，使得params数组总是相同键入 TType ，但返回值的类型 * 可能会在params数组的元素之间不同。这就是为什么我不得不选择像LambdaExpression一样更通用的东西作为类型，但是我不知道是否会有效。我可以在运行时解压缩方法中的表达式，但是当他们的两个泛型类型参数之一不同时，我很难在表达式中传递表达式。

Let's assume that the type of 'x' is a constant type. For example, if x => x.A and y => y.B were Funcs, they'd be Func<TType,*>, such that the params array always had the same type for TType, but the return value's type * could differ from element to element of the params array. That's why I had to choose something more generic like LambdaExpression as the type, but I don't know if that will work. I can unpack the expression within the method at runtime, but I'm having a hard time just trying to pass expressions to a method when one of their two generic type parameters differ.

这样就可以了，即使我不得不这样称呼：方法（a，b，（Type x）=> xA，（Type x）=> xB）

It would be fine, even if I had to call it more like: Method(a, b, (Type x) => x.A, (Type x) => x.B)

推荐答案

你可以只是编译器的帮助，将你的代码转换成表达式（与编译它）使用泛型只要。所以你必须

You can but the compiler assist that will turn your code to expression(vs compiling it) works with generics only. So you have to

Expression<Func<TType, AType>> expr1 = x => x.A;
Expression<Func<TType, BType>> expr2 = x => x.B;

Method(a, b, expr1, expr2);

或投入内线

Method(a, b, (Expression<Func<TType, AType>>) (x => x.A), expr2)

或使用更通用的参数类型

or use a more generic type of argument

void Method(object a, object b, params Expression<Func<object, object>>[] expressions)

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