Delegates

Checked with version: 4.1

-

Difficulty: Intermediate

How to create and use delegates to provide complex and dynamic functionality in your scripts.

Delegates

Intermediate Scripting

DelegateScript

Code snippet

using UnityEngine;
using System.Collections;


public class DelegateScript : MonoBehaviour 
{   
    delegate void MyDelegate(int num);
    MyDelegate myDelegate;
    

    void Start () 
    {
        myDelegate = PrintNum;
        myDelegate(50);
        
        myDelegate = DoubleNum;
        myDelegate(50);
    }
    
    void PrintNum(int num)
    {
        print ("Print Num: " + num);
    }
    
    void DoubleNum(int num)
    {
        print ("Double Num: " + num * 2);
    }
}
#pragma strict

//Javascript does not have a delegate system like 
//C# does. Instead, you can create a "Function" 
//container that works similarly to a delegate.
var myDelegate : Function;


function Start () 
{
    myDelegate = PrintNum;
    myDelegate(50);
    
    myDelegate = DoubleNum;
    myDelegate(50);
}

function PrintNum(num : int)
{
    print ("Print Num: " + num);
}

function DoubleNum(num : int)
{
    print ("Double Num: " + num * 2);
}
import UnityEngine
import System.Collections



public class DelegateScript(MonoBehaviour):

    private callable MyDelegate(num as int) as void
    private myDelegate as MyDelegate

    
    
    private def Start():
        myDelegate = PrintNum
        myDelegate(50)
        
        myDelegate = DoubleNum
        myDelegate(50)

    
    private def PrintNum(num as int):
        print(('Print Num: ' + num))

    
    private def DoubleNum(num as int):
        print(('Double Num: ' + (num * 2)))

MulticastScript

Code snippet

using UnityEngine;
using System.Collections;

public class MulticastScript : MonoBehaviour 
{
    delegate void MultiDelegate();
    MultiDelegate myMultiDelegate;
    

    void Start () 
    {
        myMultiDelegate += PowerUp;
        myMultiDelegate += TurnRed;
        
        if(myMultiDelegate != null)
        {
            myMultiDelegate();
        }
    }
    
    void PowerUp()
    {
        print ("Orb is powering up!");
    }
    
    void TurnRed()
    {
        renderer.material.color = Color.red;
    }
}
//Javascript's "Function" variable type does not
//allow for multicasting. To get this functionality
//you will need to use C#.
import UnityEngine
import System.Collections


public class MulticastScript(MonoBehaviour):

    private callable MultiDelegate() as void
    private myMultiDelegate as MultiDelegate

    
    
    private def Start():
        myMultiDelegate += PowerUp
        myMultiDelegate += TurnRed
        myMultiDelegate()
        

    
    private def PowerUp():
        print('Orb is powering up!')

    
    private def TurnRed():
        renderer.material.color = Color.red

Scripting

  1. Scripts as Behaviour Components
  2. Variables and Functions
  3. Conventions and Syntax
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  10. Interfaces
  11. Extension Methods
  12. Namespaces
  13. Lists and Dictionaries
  14. Coroutines
  15. Quaternions
  16. Delegates
  17. Attributes
  18. Events
  1. Building a Custom Inspector
  2. The DrawDefaultInspector Function
  3. Adding Buttons to a Custom Inspector
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