委托（Delegate）

委托（Delegate）是存有对某个方法的引用的一种引用类型变量

委托操作顺序

1,定义一个委托类型
2,声明了一个委托变量并且new 了一个委托对象，并且把方法传进去
3,调用委托相当于调用了方法

实例

//2, 声明了一个委托变量 md ,并且new 了一个委托对象，并且把方法M1传进去
using System.Text;
using System.Text.RegularExpressions;

MyDelegate md = new MyDelegate(M1);
// 3, 调用md委托相当于调用了M1 方法;

while (true)
{
Console.WriteLine(“请输入一个邮箱”);
string email = Console.ReadLine();
email = Regex.Replace(email, @“(\w+)(@\w+.\w+)”, ReplaceMethod,
RegexOptions.ECMAScript);
}

Console.ReadKey();

static void M1()
{
Console.WriteLine(“M1方法”);
}

static string ReplaceMethod(Match match)
{
string uid = match.Groups[1].Value;
string others = match.Groups[2].Value;
StringBuilder sb = new StringBuilder();
for (int i = 0; i < uid.Length; i++)
{
sb.Append(“*”);
}
return sb.ToString() + others;

}

//1. 定义一个委托类型，用来保存无参数，无返回值的方法
public delegate void MyDelegate();

public delegate void WriteTimeDelegate();
public class MyClass
{

}

多播委托—委托链

实例

Action action = M1;
//action(“tttt”);
action += M2;
action += M3;
action += M4;

action(“hello”);

Console.ReadKey();

static void M1(string msg)
{
Console.WriteLine(msg);
}

static void M2(string msg)
{
Console.WriteLine(msg);
}

static void M3(string msg)
{
Console.WriteLine(msg);
}

static void M4(string msg)
{
Console.WriteLine(msg);
}

实例委托传值

代码明细
Form1

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

    private void button1_Click(object sender, EventArgs e)
    {
        Form2 form2 = new Form2(textBox1.Text.Trim(),UpdateTextBox) ;
        form2.ShowDialog();
    }


    UpdateTextDelegate md = new UpdateTextDelegate(D1);


    
    static void D1(string value)
    {

    }


    public  void UpdateTextBox(string val)
    {
        textBox1.Text = val;
    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }
}

public delegate void UpdateTextDelegate(string val);

Form2
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}

    private UpdateTextDelegate _update;

    public Form2(string value,UpdateTextDelegate updateText):this()
    {
        this.textBox1.Text = value;
        this._update = updateText;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        // 将当前窗体中的文本框中的值传给 窗体1
        this._update(textBox1.Text.Trim());
        this.Close();
       
    }

    private void Form2_Load(object sender, EventArgs e)
    {

    }
}

委托传值