Question

＆＃34;如果您将值类型作为函数或方法参数，则通常按值传递。对于较大的对象，这可能会导致性能问题。在Visual Studio2013和更早版本中，C ++ / CX中的值类型始终按值传递。在Visual Studio 2015及更高版本中，您可以通过引用或值传递值类型。＆＃34;

这对我来说不起作用，使用value_struct＆amp;在函数签名中，编译器发出：

错误 C3987＆＃39;设置＆＃39;：公共成员的签名包含本机类型value_struct＆amp; ...没有参考的工作，Visual Studio 2015

我错过了什么？

Answer 1

I was able to get this to work like this:

public interface class MyDelegate {
    void MyDelegateMethod(Platform::String^ str,
        Windows::Foundation::Point *point);
}

.. and in the C# delegate implementation:

public void MyDelegateMethod(string str, out Point p) { ... }

It's mentioned in the MS page on this stuff (https://msdn.microsoft.com/en-us/library/hh699861.aspx):

You can also use a pointer symbol (*) to pass a value type by reference. The behavior with respect to callers in other languages is the same (callers in C# use the ref keyword), but in the method, the type is a pointer to the value type.

c ++ / cx通过引用传递值struct

1 个答案: