[英]pass c# struct by reference?
In my c# application i receive pointer to c++ struct in callback/delegate. 在我的c#应用程序中,我在callback / delegate中收到指向c ++ struct的指针。 I'm not sure if
class
can do the trick but just casting c++ pointer to appropriate c# struct works fine, so I'm using c# struct for storing data. 我不确定
class
可以做到这一点,但只是将c ++指针转换为适当的c#struct工作正常,所以我使用c#struct来存储数据。
Now I want to pass reference to struct for further processing 现在我想传递对struct的引用以进行进一步处理
class
because it probably will not "map" perfectly to c++ struct. class
因为它可能不会完美地“映射”到c ++ struct。 How can I do that? 我怎样才能做到这一点?
This example demonstrates that struct is passed by value, not by reference: 此示例演示struct是按值传递的,而不是通过引用传递的:
using System;
namespace TestStruct
{
struct s
{
public int a;
}
class Program
{
static void Main(string[] args)
{
s s1 = new s
{
a = 1
};
Foo(s1);
Console.WriteLine("outer a = " + s1.a);
}
private static void Foo(s s1)
{
s1.a++;
Console.WriteLine("inner a = " + s1.a);
}
}
}
Output is: 输出是:
inner a = 2
outer a = 1
It sounds like you just want to use ref
to pass the struct by reference: 听起来你只想使用
ref
通过引用传递结构:
private static void Foo(ref s s1)
{
s1.a++;
Console.WriteLine("inner a = " + s1.a);
}
And at the call site: 在通话现场:
Foo(ref s1);
See my article on parameter passing in C# for more details. 有关更多详细信息,请参阅我在C#中传递参数的文章 。
Note that other than for interop, I would normally strongly recommend against using mutable structs like this. 请注意,除了互操作之外,我通常强烈建议不要使用像这样的可变结构。 I can understand the benefits here though.
我可以理解这里的好处。
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