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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }        private void button1_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2();
            f2.Param = "hello world";
            f2.Show();
            f2.Hide();
            this.Show();
        }
    }
}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 WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }        public string Param { get; set; }        private void Form2_Load(object sender, EventArgs e)
        {
            MessageBox.Show(Param);
        }
    }
}新建2个窗体,在第一个窗体上放一个按钮,编写如上代码