C dll触发事件 [英] fire event from C dll

问题描述

我使用C编程语言和Visual Studio创建了一个dll，它在C#.net中使用，在我的应用程序中可以正常工作.现在，我需要从C编码的dll中触发一个事件，如何使用C编码创建一个事件，以及如何从其他语言调用该事件，并且我的dll不是COM组件，所以我需要从我的c dll，我正在使用[DllImport(...)]调用c dll方法.在您的C dll中创建一个函数，该函数在初始化时调用.它的参数之一是指向函数的指针.

在您的C#代码中，您调用该初始化函数并移交委托(可能需要一些

// C declaration
extern int start_something(void (*f)()) { 
 // do some stuff ...
 (*f)(); // call back to the outside
}

有时，函数指针存储在结构中或向单个函数注册，然后用于响应其他函数，但是思想是相同的.

通过P/Invoke，您可以将委托传递给具有这种签名类型的函数，即

[DllImport(...)]
public int start_something(VoidDelegate f);

public delegate void VoidDelegate();

(很抱歉，如果我忘记了如何在C中编写函数指针，那已经很长时间了:P.)

更新的C示例

I created one dll using C programming language and visual studio, Its using in C#.net its working fine in my application. Now I need to fire an event from my C coded dll, How I can create an event in C coding and how I can call it from other language and my dll is not a COM component, I need to call one of the C# function from my c dll, I am using [DllImport(...)] to invoke c dll methods

解决方案

It''s not an event as such, but you can create a function in your C dll, that is called on initialization. One of its parameters is a pointer to a function.

In your C# code, you call that initialization function and hand over a delegate (may require some marshalling[^] knowledge). That delegate points to a function that fires your desired event.

In C, when you want the event to fire, you call the callback function you were given on initialization.

''Events'' in the C world tend to be done through function pointers, i.e. you pass a function pointer to the function that starts a task, and it will be called when the task is complete.

// C declaration
extern int start_something(void (*f)()) { 
 // do some stuff ...
 (*f)(); // call back to the outside
}

Sometimes the function pointer is stored in a structure or registered with a single function and then used in response to others, but the idea is the same.

Through P/Invoke you can pass a delegate to functions with this type of signature, i.e.

[DllImport(...)]
public int start_something(VoidDelegate f);

public delegate void VoidDelegate();

(Apologies if I forgot how to write function pointers in C, it''s been a long, long time :P.)

edit: updated C sample

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