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 demo8
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void 新建NToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Form2 fm2 = new Form2();
            fm2.MdiParent = this;   //一定记得把this所在的窗体IsMdiContainer设置为true
        //a.MdiParent=this   当前窗体是窗体a的父窗体；a.MdiParent=this.MdiParent   窗体a和当前窗体的父窗体是同一个窗体
            fm2.Show();
        }

        private void 垂直平铺VToolStripMenuItem_Click(object sender, EventArgs e)
        {
            LayoutMdi(MdiLayout.TileVertical);//垂直平铺
        }

        private void 层叠ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            LayoutMdi(MdiLayout.Cascade);//层叠
        }

        private void hToolStripMenuItem_Click(object sender, EventArgs e)
        {
            LayoutMdi(MdiLayout.TileHorizontal);//水平平铺
        }

        private void lToolStripMenuItem_Click(object sender, EventArgs e)
        {
            foreach (Form childForm in MdiChildren)
            { childForm.Close(); }						//关闭子窗体
        }

    }
}

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 demo8
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)  //打开网页
        {
            try
            {
                string str = textBox1.Text.Trim();
                webBrowser1.Navigate(new Uri("http://" + str));
                this.Text = str;
            }
            catch (Exception ex) {
                MessageBox.Show(ex.Message.ToString());
            }
        }

        private void button2_Click(object sender, EventArgs e)  //刷新
        {
            webBrowser1.Refresh();
        }

        private void button3_Click(object sender, EventArgs e) //上一页
        {
            webBrowser1.GoBack();
        }

        private void button4_Click(object sender, EventArgs e)//下一页
        {
            webBrowser1.GoForward();
        }

    }
}