myNotepad.cs

using System;
using System.Windows.Forms;
using System.IO;//Input Output

namespace MyNotepad
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void saveToolStripMenuItem_Click(object sender, EventArgs e)
        {
            //File -> Save
            //1. Open File Dialog
            saveFileDialog1.ShowDialog();//Open windows
            string path = saveFileDialog1.FileName;//File path
            //2. Create File
            //3. Text -> File
            string[] text = richTextBox1.Lines;
            File.WriteAllLines(path, text);//Create+Write+Close
            //4. Close File
        }

        private void openToolStripMenuItem_Click(object sender, EventArgs e)
        {
            // 1- Open Dialog
            openFileDialog1.ShowDialog();
            string path = openFileDialog1.FileName;
            // 2- Read File -> Text
            string[] text = File.ReadAllLines(path);
            richTextBox1.Lines = text;
        }

        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.menuStrip1 = new System.Windows.Forms.MenuStrip();
            this.fileToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.openToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.saveToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.exitToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.richTextBox1 = new System.Windows.Forms.RichTextBox();
            this.saveFileDialog1 = new System.Windows.Forms.SaveFileDialog();
            this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
            this.menuStrip1.SuspendLayout();
            this.SuspendLayout();
            // 
            // menuStrip1
            // 
            this.menuStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.fileToolStripMenuItem});
            this.menuStrip1.Location = new System.Drawing.Point(0, 0);
            this.menuStrip1.Name = "menuStrip1";
            this.menuStrip1.Size = new System.Drawing.Size(281, 24);
            this.menuStrip1.TabIndex = 0;
            this.menuStrip1.Text = "menuStrip1";
            // 
            // fileToolStripMenuItem
            // 
            this.fileToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.openToolStripMenuItem,
            this.saveToolStripMenuItem,
            this.exitToolStripMenuItem});
            this.fileToolStripMenuItem.Name = "fileToolStripMenuItem";
            this.fileToolStripMenuItem.Size = new System.Drawing.Size(37, 20);
            this.fileToolStripMenuItem.Text = "File";
            // 
            // openToolStripMenuItem
            // 
            this.openToolStripMenuItem.Name = "openToolStripMenuItem";
            this.openToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.O)));
            this.openToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
            this.openToolStripMenuItem.Text = "Open";
            this.openToolStripMenuItem.Click += new System.EventHandler(this.openToolStripMenuItem_Click);
            // 
            // saveToolStripMenuItem
            // 
            this.saveToolStripMenuItem.Name = "saveToolStripMenuItem";
            this.saveToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.S)));
            this.saveToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
            this.saveToolStripMenuItem.Text = "Save";
            this.saveToolStripMenuItem.Click += new System.EventHandler(this.saveToolStripMenuItem_Click);
            // 
            // exitToolStripMenuItem
            // 
            this.exitToolStripMenuItem.Name = "exitToolStripMenuItem";
            this.exitToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Alt | System.Windows.Forms.Keys.F4)));
            this.exitToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
            this.exitToolStripMenuItem.Text = "Exit";
            this.exitToolStripMenuItem.Click += new System.EventHandler(this.exitToolStripMenuItem_Click);
            // 
            // richTextBox1
            // 
            this.richTextBox1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.richTextBox1.Font = new System.Drawing.Font("Times New Roman", 24F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.richTextBox1.Location = new System.Drawing.Point(0, 24);
            this.richTextBox1.Name = "richTextBox1";
            this.richTextBox1.Size = new System.Drawing.Size(281, 259);
            this.richTextBox1.TabIndex = 1;
            this.richTextBox1.Text = "";
            // 
            // saveFileDialog1
            // 
            this.saveFileDialog1.DefaultExt = "txt";
            // 
            // openFileDialog1
            // 
            this.openFileDialog1.FileName = "openFileDialog1";
            this.openFileDialog1.Filter = "Text|*.txt";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(281, 283);
            this.Controls.Add(this.richTextBox1);
            this.Controls.Add(this.menuStrip1);
            this.MainMenuStrip = this.menuStrip1;
            this.Name = "Form1";
            this.Text = "My Notepad";
            this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
            this.menuStrip1.ResumeLayout(false);
            this.menuStrip1.PerformLayout();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.MenuStrip menuStrip1;
        private System.Windows.Forms.ToolStripMenuItem fileToolStripMenuItem;
        private System.Windows.Forms.ToolStripMenuItem openToolStripMenuItem;
        private System.Windows.Forms.ToolStripMenuItem saveToolStripMenuItem;
        private System.Windows.Forms.ToolStripMenuItem exitToolStripMenuItem;
        private System.Windows.Forms.RichTextBox richTextBox1;
        private System.Windows.Forms.SaveFileDialog saveFileDialog1;
        private System.Windows.Forms.OpenFileDialog openFileDialog1;
    }
}