窗体传值

Form1：

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 _147_窗体传值
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Form2 form2 = new Form2(ShowMsg);
            form2.Show();
        }
        void ShowMsg(string str)
        {
            label1.Text = str;
        }
    }
}

From2：

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 _147_窗体传值
{
    //声明委托
    public delegate void DelTest(string str);
    public partial class Form2 : Form
    {
        //声明一个字段
        private DelTest _del;
        public Form2(DelTest del)
        {
            this._del = del;
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            _del(textBox1.Text);
        }
    }
}