using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Reflection;using System.Text;using System.Threading.Tasks;using System.Windows.Forms;namespace MDITest{  public partial class MainForm : Form  {    public MainForm()    {      InitializeComponent();    }    public int[] s = { 0, 0, 0 };//用來記錄窗體是否打開過    private void MainForm_Load(object sender, EventArgs e)    {      //默認加載CNC窗體      string formClass = "MDITest.CNC";      GenerateForm(formClass, tabControl1);    }    public void GenerateForm(string form,object sender)    {      //反射生成窗體      Form fm = (Form)Assembly.GetExecutingAssembly().CreateInstance(form);      //設置窗體沒有邊框，加入到選項卡中      fm.FormBorderStyle = FormBorderStyle.None;       fm.TopLevel = false;       fm.Parent = ((TabControl)sender).SelectedTab;       fm.ControlBox = false;       fm.Dock = DockStyle.Fill;       fm.Show();      s[((TabControl)sender).SelectedIndex] = 1;     }    private void tabControl1_SelectedIndexChanged(object sender, EventArgs e)    {      //只生成一次      if(s[tabControl1.SelectedIndex]==0)      {        btn_Click(sender,e);      }    }         /// <summary>     /// 通用按鈕點擊選項卡 在選項卡上顯示對應的窗體     /// </summary>     private void btn_Click(object sender,EventArgs e)    {      string formClass=((TabControl)sender).SelectedTab.Tag.ToString();      GenerateForm(formClass, sender);    }  }}