invoke method with reflection C#

Questions & Answers
1

using UnityEngine;
using System.Collections;
using System;
using System.Reflection;

public class blblb : MonoBehaviour
{

    void Start()
    {
        Type thisType = this.GetType();
        MethodInfo theMethod = thisType.GetMethod("bla");
        theMethod.Invoke(this, null);
    }

    private void bla()
    {
        Debug.Log("enters");
    }
}

NullReferenceException: Object
reference not set to an instance of an
object blblb.Start () (at
Assets/blblb.cs:13)

What am I doing wrong to get this error?

P.S I know there’s Invoke method in unity. I need to know how to use the reflection way.

4

This is an example on how to get instance methods. It works for me so there is no reason it should break for you.

private Action myAction = ()=>{};

void Start()
{
   System.Type ourType = this.GetType(); 

   MethodInfo mi= ourType.GetMethod("MyMethod", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
        
   if (mi!= null){
       myAction = (Action)Delegate.CreateDelegate(typeof(Action), this, mi);
   }
}

then you can call myAction(); like any other methods.

This has the advantage of allowing sub class to contain methods or not just like Unity does for Update/LateUpdate or other events. Your top class may contain all the checks and the sub class just implements or not.

3

msdn documentation on GetMethod().

“Searches for the public method with the specified name.”

Simply make your bla method public :wink:

Note:
The easiest way to debug this kind of stuff is to use Debug.Log() statements.

void Start ()
{
	Type thisType = this.GetType();

	Debug.Log ("Type: " + thisType);

	MethodInfo theMethod = thisType.GetMethod("bla");

	Debug.Log ("MethodInfo: " + theMethod);

	theMethod.Invoke(this, null);
}

theMethod variable is null, since the bla method is private and cannot be found (hence the NullReferenceException).

2

Well first of all, don’t type “this”, because thats just going to cause errors…

Change your code to:

Invoke (“YourFunction”, 0);

assuming the name of your function is YourFunction.