C# AE之返回上一级和下一级的实战操作

try
      {
        //判断是否可以返回上一视图
        if (mapControl.ActiveView.ExtentStack.CanUndo())
        {
          //执行操作
          mapControl.ActiveView.ExtentStack.Undo();
          //刷新
          mapControl.Refresh();
        }
      }
      catch (Exception ex)
      {
        throw;
      }

 try
      {
        if (mapControl.ActiveView.ExtentStack.CanRedo())
        {
          mapControl.ActiveView.ExtentStack.Redo();
          mapControl.Refresh();
        }
      }
      catch (Exception ex)
      {
        throw;
      }

private void button1_Click(object sender, EventArgs e)
{
Form2 form2 = new Form2(this);//把form1传给form2
this.Hide();//把自己隐藏了
//form2.ShowDialog();//2种显示方法都可以
form2.Show();
}

public partial class Form2 : Form
{
Form1 _form1;
public Form2(Form1 form1)
{
InitializeComponent();
_form1 = form1;
}
private void button1_Click(object sender, EventArgs e)
{
//把自己关闭，并显示Form1
this.Close();
_form1.Show();
}
}

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
th = new Thread(new ThreadStart(StartNewForm));
}
private Thread th;
private void StartNewForm()
{
From1 mf = new From2();
Application.Run(mf);//启动主界面
}
private void close_Click(object sender, EventArgs e)
{
this.Close();//关闭窗体
th.Start();//启动另一个线程
}
}