winform 新建窗体

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace 新建窗体
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void 这是一ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            bool has = false;
            Form2 f2 = new Form2();
            f2.WindowState = FormWindowState.Maximized;//最大化窗口
            foreach (Form f in this.MdiChildren)
            {
                if (f.Name == f2.Name)//这是名字相同，已经打开后在打开
                {
                    has = true;
                    f.WindowState = FormWindowState.Maximized;//最大化窗口
                    f.Show();
                    f2.Close();
                }
            }
            if (has)
            {
                foreach (Form f in this.MdiChildren)
                {
                    if (f.Name != f2.Name)//打开的名字不同，隐藏第一个
                    {
                        f.Hide();//隐藏
                    }
                }
            }
            else //第一次打开窗口
            {
                f2.WindowState = FormWindowState.Maximized;//最大化窗口
                f2.MdiParent = this;//获取此窗口的父及窗口
                
                f2.Show();//显示
            }
        }

        private void 这是二ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            bool has = false;
            Form3 f3 = new Form3();
            f3.WindowState = FormWindowState.Maximized;//最大化窗口
            foreach (Form f in this.MdiChildren)
            {
                if (f.Name == f3.Name)
                {

                    has = true;
                    f.WindowState = FormWindowState.Maximized;//最大化窗口
                    f.Show();
                    f3.Close();
                }
            }
            if (has)
            {
                foreach (Form f in this.MdiChildren)
                {
                    if (f.Name != f3.Name)
                    {
                        f.Hide();
                    }
                }
            }
            else 
            {
                f3.WindowState = FormWindowState.Maximized;//最大化窗口
                f3.MdiParent = this;//获取此窗口的父及窗口
                
                f3.Show();
            }
        }
    }
}