如何在扩展方法中使用函数作为参数? [英] how to use a function as parameter in extension method?

问题描述

我已阅读建议在扩展方法中使用函数而不是谓词，因此我正在尝试这样做.

I have read that is recomended to use functions instead of predicates in the extension methods, so I am trying to do it.

public static void Insert<T>(this ObservableCollection<T> paramOC, T NewElement, Func<T, T, bool> condition)
        {
            //code
        }

我正试图以这种方式使用:

I am trying to use in this way:

myOC.Insert(myNewElement, e=>e.Name.CompareTo(myNewElement.Name) > 0));

但是我收到一条错误消息，指出delete System.Func不带1个参数.

But I get an error that says that the delete System.Func does not take 1 argument.

但是，如果我使用该函数的谓词inadad，它将起作用.

However, if I use a predicate intead of the function, it works.

我想念什么?

非常感谢.

推荐答案

您需要Func<T,bool>(需要一个参数并返回bool)，而不是Func<T,T,bool>

You need Func<T,bool> (which takes one argument and returns bool), not Func<T,T,bool>

Predicate<T>之所以有效，是因为它接受一个参数并返回bool，因此它与 lambda表达式匹配.Func<T,T,bool>需要两个参数并返回与表达式不匹配的布尔值因此是错误.

Predicate<T> works because it takes one argument and returns bool, so it matches with the lambda expression.Func<T,T,bool> expects two arguments and returns bool which doesn't match with your expression hence the error.

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