MDIParent1.cs

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 WindowsFormsApplication1
{
    public partial class MDIParent1 : Form
    {
        Form1 f1 = new Form1();
        private int childFormNumber = 0;
        public MDIParent1()
        {
            InitializeComponent();
        }
        private void OpenFile(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
            openFileDialog.Filter = "Txt(*.txt)|*.txt|all file(*.*)|*.*";
            if (openFileDialog.ShowDialog(this) == DialogResult.OK)
            {
                string FileName = openFileDialog.FileName;
            }
        }
        private void SaveAsToolStripMenuItem_Click(object sender, EventArgs e)
        {
            SaveFileDialog saveFileDialog = new SaveFileDialog();
            saveFileDialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
            saveFileDialog.Filter = "Txt(*.txt)|*.txt|all file(*.*)|*.*";
            if (saveFileDialog.ShowDialog(this) == DialogResult.OK)
            {
                string FileName = saveFileDialog.FileName;
            }
        }
        private void ExitToolsStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Close();
        }
        private void ToolBarToolStripMenuItem_Click(object sender, EventArgs e)
        {
            toolStrip.Visible = toolBarToolStripMenuItem.Checked;
        }
        private void StatusBarToolStripMenuItem_Click(object sender, EventArgs e)
        {
            statusStrip.Visible = statusBarToolStripMenuItem.Checked;
        }
        private void CascadeToolStripMenuItem_Click(object sender, EventArgs e)
        {
            LayoutMdi(MdiLayout.Cascade);
        }
        private void TileVerticalToolStripMenuItem_Click(object sender, EventArgs e)
        {
            LayoutMdi(MdiLayout.TileVertical);
        }

        private void TileHorizontalToolStripMenuItem_Click(object sender, EventArgs e)
        {
            LayoutMdi(MdiLayout.TileHorizontal);
        }

        private void ArrangeIconsToolStripMenuItem_Click(object sender, EventArgs e)
        {
            LayoutMdi(MdiLayout.ArrangeIcons);
        }
        private void CloseAllToolStripMenuItem_Click(object sender, EventArgs e)
        {
            foreach (Form childForm in MdiChildren)
            {
                childForm.Close();
                childFormNumber = 0;
            }
        }
        private void Test_Click(object sender, EventArgs e)
        {
            f1.Show();
            childFormNumber++;
        }
        private void MDIParent1_Load(object sender, EventArgs e)
        {
            f1.MdiParent = this;
            f1.Show();
            childFormNumber++;
        }
    }
}