dropdown does not contain a defanition for on value changed

Unity Engine
1

hi guys
im gettin the error
“dropdown does not contain a defanition for ‘value’”
and am not shore why

here is my code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class Dropdown : MonoBehaviour {
public Dropdown drop;

void Update () {
if (drop.value == 0){
//do something
}
}

unity 5.5.2f1

2

Why did you post this twice?