using System;
using System.Windows.Forms;
using System.IO;

class ex : Form
{
    TextBox tb1 = new TextBox();

    ex()
    {
        Text = "hello";
        tb1.Dock = DockStyle.Fill;
        tb1.Multiline = true;
        Controls.Add(tb1);

        MenuStrip ms = new MenuStrip();
        Controls.Add(ms);
        ToolStripMenuItem File = new ToolStripMenuItem("File");
        ms.Items.Add(File);

        ToolStripMenuItem mi1 = new ToolStripMenuItem("Open");
        mi1.Click += new EventHandler(Open_Click);
        File.DropDownItems.Add(mi1);

        ToolStripMenuItem mi2 = new ToolStripMenuItem("Save");
        mi2.Click += new EventHandler(Save_Click);
        File.DropDownItems.Add(mi2);
    }

    void Open_Click(object sender, EventArgs e)
    {
        OpenFileDialog ofd = new OpenFileDialog();

        if (ofd.ShowDialog() == DialogResult.OK)
        {
            tb1.Text = File.ReadAllText(ofd.FileName);
        }
    }

    void Save_Click(object sender, EventArgs e)
    {
        SaveFileDialog sfd = new SaveFileDialog();
        sfd.DefaultExt = "txt";

        if (sfd.ShowDialog() == DialogResult.OK)
        {
            File.WriteAllText(sfd.FileName, tb1.Text);
        }
    }

    [STAThread]
    static public void Main()
    {
        Application.Run(new ex());
    }
}