如何使用LINQ在C ++ / CLI - 在VS 2010 / .NET 4.0 [英] How to use LINQ in C++/CLI - in VS 2010/.Net 4.0

问题描述

只是不知道是否有一种方法可以使用​​LINQ在C ++ / CLI。我发现的重点是VS 2008和要求一堆的解决方法系统:: String类的一个职位。我看到的$ C $的CProject一些框架的替代品，但我不知道是否有一种方法可以在C ++ / CLI直接使用它。如果可以的话，任何人有一个很好的例子？

Just wondering if there is a way to use LINQ in C++/CLI. I found one post that was focused on VS 2008 and required a bunch of workarounds for the System::String class. I have seen some framework replacements on CodeProject, but I was wondering if there is a way to use it directly in C++/CLI. If you can, anyone have a good example?

推荐答案

您可以使用在系统：LINQ的命名空间中定义的LINQ的方法，但你'马上要跳，通过一对额外的篮球。

You can use the Linq methods that are defined in the System::Linq namespace, but you'll have to jump through a couple extra hoops.

首先，C ++ / CLI不支持扩展方法。然而，扩展方法是对不同类定义的常规方法系统：LINQ的，这样你就可以直接调用它们。

First, C++/CLI doesn't support extension methods. However, the extension methods are regular methods defined on various classes in System::Linq, so you can call them directly.

List<int>^ list = gcnew List<int>();
int i = Enumerable::FirstOrDefault(list);

二，C ++ / CLI不支持拉姆达EX pressions。唯一的解决方法是宣布一个实际的方法，并传递作为代表。

Second, C++/CLI doesn't support lambda expressions. The only workaround is to declare an actual method, and pass that as a delegate.

ref class Foo
{
public:
    bool GreaterThanZero(int i) { return i > 0; }

    void Bar()
    {
        List<int>^ list = gcnew List<int>();
        int i = Enumerable::FirstOrDefault(list, gcnew Func<int, bool>(&Foo::GreaterThanZero));
    }
}

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