C#高级语法_委托

主从窗体之间的通信

主窗体:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class FrmMain : Form
    {
        public FrmMain()
        {
            InitializeComponent();

        }

        //2.根据委托定义方法
        private void ReceiveMsg(string msg, string consoleName)
        {
            this.label1.Text += $"来自{consoleName}的消息:{msg}\r\n";
        }

        /// <summary>
        /// 创建子窗体
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            for (int i = 1; i < 4; i++)
            { 
                Form1 form = new Form1($"子窗体{i}");
                //4.委托变量和方法关联
                form.delegateReceiveMsg += ReceiveMsg;
                form.Show();
            }
        }

        /// <summary>
        /// 关闭子窗体
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button3_Click(object sender, EventArgs e)
        {
            // 遍历所有打开的窗体
            // 使用ToList()创建副本，避免在遍历中修改集合引发异常
            foreach (var form in Application.OpenForms.OfType<Form1>().ToList())
            {
                // 关闭子窗体
                form.Close();
            }
        }
    }

    //1.定义委托
    public delegate void DelegateMsgBtoA(string msg, string consoleName);
}

子窗体:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        //3.创建委托变量
        public DelegateMsgBtoA delegateReceiveMsg = delegate { };

        public Form1()
        {
            InitializeComponent();
        }

        public Form1(string name)
        {
            InitializeComponent();        
            this.Text = name;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //5.通过委托变量调用方法
            delegateReceiveMsg.Invoke(this.textBox1.Text, this.Text);
        }
    }
}