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

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 F = new Form2();
            F.ABC += QQQ;//绑定（中介）事件
            F.Show();
        }
        int chuanhui = 123;
        void QQQ(string B, ref int AA)
        {
            AA = chuanhui;//返回子窗体的值
        }

       
            
    }
}

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 窗体传值
{
    public partial class Form2 : Form
    {
        public delegate  void D1(string A,ref int B);
        public event D1 ABC;
        public Form2()
        {
            InitializeComponent();
        }
        int BB;
        private void button1_Click(object sender, EventArgs e)
        {
            ABC("111", ref BB);//执行（中介）事件
        }

        private void button2_Click(object sender, EventArgs e)
        {
            MessageBox.Show(BB.ToString());//获取主窗体的值
        }
    }
}