有什么方法可以将lambda表达式作为变量或参数传递? [英] Is there any way to pass the lambda expression as a variable or argument?

问题描述

我需要将lambda查询作为参数传递，以下代码为示例，我很高兴为它找到一个实现，有示例:像这样的东西:

I need to pass the lambda query as a parameter, the followings code is sample and I am interesting to find an implement for it, there is samples: some thing like this:

var expr1 = Where(n => n > 6).OrderBy(n => n % 2 == 0).Select(n => n);
var expr2 = TakeWhile((n, index) => n >= index));

并像这样使用它:

public void UseLambda<T> (IEnumerable<T> source , lambda Expr){

var items= Expr.Compile(source);

foreach(var item in items)
     Console.Writeline(item.ToString());
}

public void Main(){
    List<int> numbers = new List<int> { 10, 24, 9, 87, 193, 12, 7, 2, -45, -2, 9 };
    var expr1 = Where(n => n > 6).OrderBy(n => n % 2 == 0).Select(n => n);
    UseLambda(numbers, expr1);
}

有人对此有想法吗?

推荐答案

如果您这样定义LINQ表达式:

If you define your LINQ expressions like this:

Func<IEnumerable<int>, IEnumerable<int>> expr1 =
               l => l.Where(n => n > 6).OrderBy(n => n % 2 == 0).Select(n => n);

Func<IEnumerable<int>, IEnumerable<int>> expr2 = 
               l => l.TakeWhile((n, index) => n >= index);

您的UseLambda方法如下:

And your UseLambda method as:

public void UseLambda<T> (IEnumerable<T> source 
                          ,Func<IEnumerable<T>, IEnumerable<T>> lambda)
{
    var items= lambda(source);

    foreach(var item in items)
       Console.Writeline(item.ToString());
    }
}

那你我想你有想要的东西.

Then you I think you have what you're looking for.

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