Difference between delegate Action and Func: Delegate actionfunc

Difference between delegate Action and Func: Delegate actionfunc
I. Description

Generally, we define the delegate as follows:

Public delegate void MyDelegate (string name); // defines the delegate

Public MyDelegate myDelegate; // use the delegate

However,. Net also provides defined delegation, which can be used directly.

Ii. Definition

System. Action No Return Value

Action:public delegate void Action ();Action< T >:public delegate void Action< T > (T obj);Action< T1, T2 >：public delegate void Action< T1, T2 > (T1 arg1, T2 arg2);

* delegate void Action<T1,T2,T3,T4>T1 arg1, T2 arg2, T3 arg3, T4 arg4);

 

System. Func has returned values.

Func< TResult >public delegate TResult Func< TResult > ();Func< T,TResult >public delegate TResult Func< T, TResult > (T arg);Func< T1,T2,TResult >public delegate TResult Func< T1, T2, TResult > (T1 arg1, T2 arg2);

*delegate TResult Func<T1,T2,T3,T4,TResult>T1 arg1, T2 arg2, T3 arg3, T4 arg4);

Iii. Use

Example 1: Action

using UnityEngine;using System.Collections;using System;public class ActionTest : MonoBehaviour {    void Start () {        Action action = XXX;        action();    }    void XXX()    {        Debug.Log("100");    }}

Example 2: Action <T> using UnityEngine; using System. collections; using System; public class ActionTest: MonoBehaviour {void Start () {Action <string> action = XXX; action ("unity C #");} void XXX (string name) {Debug. log (name );}}

Example 3: Action <T1, T2> using UnityEngine; using System. collections; using System; public class ActionTest: MonoBehaviour {void Start () {Action <string, int> action = XXX; action ("unity C #", 100 );} void XXX (string name, int score) {Debug. log (string. format ("{0} {1}", name, score );}}

# Region Action usage // Action <T> usage // here T is the input type of the proxy function, no return value Action <string []> action = delegate (string [] x) {var result = from p in x where p. contains ("s") select p; foreach (string s in result. toList () {Console. writeLine (s) ;}}; string [] str = {"charlies", "nancy", "alex", "jimmy", "selina"}; action (str ); console. readKey (); # endregion

In the preceding example, an array of the String type is input to find the item containing the character s and output it to the console.

Example 4: Func <TResult> using UnityEngine; using System. collections; using System; public class FuncTest: MonoBehaviour {void Start () {Func <int> func = XXX; Debug. log (func ();} int XXX () {return 10 ;}}

Example 5: Func <T, TResult> using UnityEngine; using System; public Class FuncTest: MonoBehaviour {void Start () {Func <string, int> func = CallStringLength ;} int CallStringLength (string str) {return str. lenth ;}}

Func <string> func = delegate () {return "I am the result returned by Func <TResult> delegate ";}

Predicate can only accept one input parameter. The returned value is of the bool type.

# Region Predicate // bool Predicate <T> usage // enter a T-type parameter, return Value: Boolean Predicate <string []> predicate = delegate (string [] x) {var result = from p in x where p. contains ("s") select p; if (result. toList (). count> 0) {return true;} else {return false ;}; string [] _ value = {"charlies", "nancy", "alex", "jimmy ", "selina"}; if (predicate (_ value) {Console. writeLine ("They contain. ");} else {Console. writeLine ("They don't contain. ");} Console. readKey (); # endregion

The above code is used to determine whether the String array contains s items. If yes, the They contain will be printed on the console. If no, the They don't contain will be printed.

// Define public void CallUI <T> (Action <T, object []> callback, params object [] args) where T: CUIBase // call CUIManager. instance. callUI <CUIMidMsg> (_ ui, _ arg) => _ ui. showMsg (string) _ arg [0]), string. format (szMsg, format ));

Part of the Reference: Fengyu Chong Unity3D tutorial Institute

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