从C ++迁移到C＃（回叫）

Question

I am currently doing a migration of c++ to c # and I presented the following problem which I have not the faintest idea as can be done within c #

typedef void (CALLBACK *funtion1)(int a , int b);

void SetCallBackFuntion(funtion1 pfn);


void something(){

obj->SetCallBackFuntion(&funtion1);

}

Answer 1

There are a few ways to achieve the equivilant behaviour in C# depending on how you want it to work and what version of .NET you're targeting. The easiest method is to use an Action .

To implement this using C# standards it should first be noted that it fits better as a property rather than a method. Also, because the callback doesn't return a value it's referred to as a method, not a function. So the code above would look something like this:

public Action<int,int> CallBack { set; }

public void Something()
{
    obj.CallBack = function1;
}

And the code to call the callback would do something like this:

if(CallBack != null)
    CallBack(1, 2);

Another approach is to use a delegate , which is just a slightly more verbose way of describing an Action and compatible with older versions of .NET. It also translates more closely with the C++ code. Note: Although this would technically work (assuming you implemented the rest correctly) it's not normally regarded as good practice. I just wanted to show you a quick and dirty way.

public delegate void CallBack(int x, int y);

private void SetCallBackFuntion(CallBack pfn)
{
}

private void Something()
{
    obj.SetCallBackFuntion(funtion1);
}

A third approach is to use interfaces. You could describe an interface with your method signature like this:

public interface IMyInterface
{
    void CallBack(int x, int y);
}

and then you could have a property on your class similar to the Action but using the interface instead.

public IMyInterface CallBackObject { set; }

public void Something()
{
    obj.CallBackObject = someObject;
}

if(CallBackObject != null)
    CallBackObject.CallBack(1, 2);

The final approach that comes to mind is to use event handlers, but since they are more useful when you have multiple subscribers to your callback, I won't cover them here.

Answer 2

可以使用委托简单地用C＃编写