C#使用MonoPInvokeCallback，让C直接回调C#函数

Test.mm

char* TestMakeCString(NSString *str) {
    const char* string = [str UTF8String];
    if (string == NULL) {
        return NULL;
    }
    
    char* res = (char*)malloc(strlen(string) + 1);
    strcpy(res, string);
    return res;
}

extern "C"{
    typedef void (*TestCallback)(const char*eventName);
    TestCallback _myCallback;
    void _TestInit(TestCallback callback){
        _myCallback=callback;
    }
}

@implementation Test
-(void) test{
    _myCallback(TestMakeCString(@"complete"));
}
@end

Test.cs

using System.Runtime.InteropServices;
public class Test{
    public delegate void EventHandler(string eventName, string msg);
    public event EventHandler callbackHandler;
    
    internal delegate void TestCallBack(string eventName);
    [DllImport("__Internal")]
    private static extern void _TestInit(TestCallBack callback);
    
    [MonoPInvokeCallback(typeof(TestCallBack))]
    public static void onCallBack(string eventName){
        if(eventName=="complete"){
            //do something
            if(callbackHandler!=null)callbackHandler(eventName,"HIJK");
        }
    }

     public static Test _instance;
     public static Test getInstance(){
     　　if(_instance==null){
         　　_instance=new Test();
     　　}
     　　return _instance;
      }
        
    //初始接口
    public void init(){
        _TestInit(onCallBack);
    }

}

demo:

Test test=Test.getInstance()
test.init();
test.callbackHandler+=handler;

void handler(string eventName,string msg){
　　//do something
}