构造函数实现窗体间传值

///Form1.cs  the form contains a textbox and a button
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace 窗体间通迅
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 frm = new Form2(this.textBox1);
            frm.Show();

        }
    }
}

///Form2.cs  the form contains a textbox and a button
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace 窗体间通迅
{
    public partial class Form2 : Form
    {
        private delegate void dg();

        /// <summary>
        /// 让其与窗体1的TextBox1同一个引用。
        /// </summary>
        private TextBox textBox12;

        public Form2()
        {
            InitializeComponent();
        }

        public Form2(TextBox txtBox)
        {
            InitializeComponent();
            textBox1.Text = txtBox.Text; ;
            this.textBox12 = txtBox;
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            textBox12 .Text  = textBox1.Text;
            this.Close();
            
        }
    }
}