通过引用传递 c# 结构？
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pass c# struct by reference?
提问by javapowered
In my c# application i receive pointer to c++ struct in callback/delegate. I'm not sure if classcan do the trick but just casting c++ pointer to appropriate c# struct works fine, so I'm using c# struct for storing data.
在我的 c# 应用程序中，我在回调/委托中收到指向 c++ 结构的指针。我不确定是否class可以做到这一点，但只是将 c++ 指针转换为适当的 c# 结构可以正常工作，所以我使用 c# 结构来存储数据。
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
- I can't use
classbecause it probably will not "map" perfectly to c++ struct. - I don't want to copy struct for better latency
- 我不能使用，
class因为它可能不会完美地“映射”到 C++ 结构。 - 我不想复制结构以获得更好的延迟
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:
这个例子演示了 struct 是按值传递的，而不是按引用传递：
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
采纳答案by Jon Skeet
It sounds like you just want to use refto pass the struct by reference:
听起来您只想使用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:
在呼叫站点：
Foo(ref s1);
See my article on parameter passing in C#for more details.
有关更多详细信息，请参阅我关于在 C# 中传递参数的文章。
Note that other than for interop, I would normally strongly recommend againstusing mutable structs like this. I can understand the benefits here though.
请注意，除了互操作之外，我通常强烈建议不要使用这样的可变结构。不过，我可以理解这里的好处。
