主窗体含有控件Button，DataGridView

主窗体button按钮点击函数打开弹窗

        private void add_Click(object sender, EventArgs e)
        {
            DictAdd form = new DictAdd();
            form.cleareven();//去掉事件委托
            form.ev += nationload;//添加事件委托
            form.ShowDialog();
        }

弹窗C#代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace Learn
{
    public partial class DictAdd : Form
    {
        public delegate void TableRefres(string bh, string name);
        public event TableRefres ev;//委托方法  用于  刷新主窗体

        /// <summary>
        /// 去掉事件委托
        /// </summary>
        public void cleareven()
        {
            if (ev != null)
            {
                Delegate[] ar = ev.GetInvocationList();
                if (ar.Length > 0)
                {
                    foreach (Delegate a in ar)
                    {
                        ev -= a as TableRefres;
                    }
                }
            }
        }
        public DictAdd()
        {
            InitializeComponent();
        }
    
        //刷新主窗体函数
        private void button1_Click(object sender, EventArgs e)
        {
            ev("", "");
        }
    }
}

主窗体刷新函数

public void load(string bh, string name)

弹窗定义TableRefres    然后声明ev事件

public delegate void TableRefres(string bh, string name);//保证参数一致