c# 中Delegate，Action，Func，Predicate的区别及用法

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1.Delegate，Action（常用）

#region 模块信息
// **********************************************************************
// Copyright (C) 2018 Blazors
// Please contact me if you have any questions
// File Name:             GameDefine
// Author:                romantic123fly
// WeChat||QQ:            at853394528 || 853394528 
// **********************************************************************
#endregion
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.UI;
public delegate void MyDelegate(string name);//定义委托
public delegate void Action();
public delegate void Action<T>(T obj);
public delegate void Action<T1, T2>(T1 arg1, T2 arg2);
public class ActionTest : MonoBehaviour {
    public MyDelegate myDelegate; //使用委托

    Action action;
    Action<string> action1;
    Action<string, int> action2;
    Action<string[]> action3;
    void Start()
    {
        myDelegate += DelegateFun;
        myDelegate("myDelegate");


        action += test1;//无参数
        action();

        action1 += test2;//一个参数
        action1("Test2");

        action2 += test3;//两个参数
        action2("Test3", 99);

        action3 += test4;//集合参数
        action3(new string[] { "charlies", "nancy", "alex", "jimmy", "selina" });
    }

    private void DelegateFun(string name)
    {
        Debug.Log(name);
    }

    void test1()
    {
        Debug.Log("test1");
    }
    void test2(string str)
    {
        Debug.Log(str);
    }
    void test3(string str,int num)
    {
        Debug.Log(string.Format("{0}  {1}", str, num));
    }

    void test4(string[] x)
    {
        var result = from o in x where o.Contains("s")select o;
        foreach (string s in result.ToList())
        {
            Debug.Log(s);
        }
    }
}

2.Func，Predicate

Func可以传入多个参数，默认最后一个为返回值
Predicate只能接受一个传入参数，返回值为bool类型

#region 模块信息
// **********************************************************************
// Copyright (C) 2018 Blazors
// Please contact me if you have any questions
// File Name:             GameDefine
// Author:                romantic123fly
// WeChat||QQ:            at853394528 || 853394528 
// **********************************************************************
#endregion
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

//有返回值的委托
public delegate TResult Func<TResult>();
public delegate TResult Func<T, TResult>(T arg);
public delegate TResult Func<T1, T2, TResult>(T1 arg1, T2 arg2);

public class FuncTest : MonoBehaviour
{
    Func<int> func;
    Func<string, int> func1;
    Predicate<string[]> predicate;
    void Start()
    {
        func = XXX;
        Debug.Log(func());
        func1 = CallStringLength;
        Debug.Log(func1("sadasdads"));

        ///bool Predicate<T>的用法
        ///输入一个T类型的参数,返回值为bool类型
        predicate = func2;


        string[] _value = { "charlies", "nancy", "alex", "jimmy", "selina" };
        Debug.Log(predicate(_value));
    }

    private bool func2(string[] obj)
    {
        var result = from p in obj
                     where p.Contains("s")
                     select p;
        if (result.ToList().Count > 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    int XXX()
    {
        return 10;
    }
    int CallStringLength(string str)
    {
        return str.Length;
    }
}