C ＃ uses monopinvokecallback to directly call back C ＃ function

iOS Code ：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

 C# Code ：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;
      }
        
    // Initial interface 
    public void init(){
        _TestInit(onCallBack);
    }

}

 test demo:

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

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