What is File handling in C#?

Question

If write this code in form 1 :

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;
using System.IO;
using System.Xml.Serialization;

namespace PostLab5_**********
{
    public partial class Form1 : Form
    {
        List<StudentInfo> Stu_Info = new List<StudentInfo>();
        Queue<StudentInfo> pass = new Queue<StudentInfo>();
        Queue<StudentInfo> fail = new Queue<StudentInfo>();
        Stack<StudentInfo> Excelent = new Stack<StudentInfo>();
        Stack<StudentInfo> VeryGood = new Stack<StudentInfo>();
        Stack<StudentInfo> Good = new Stack<StudentInfo>();
        public Form1()
        {
            InitializeComponent();
        }

        private void importXMLToolStripMenuItem_Click(object sender, EventArgs e)
        {

            OpenFileDialog Dlg = new OpenFileDialog();
            Dlg.Filter = "XML File|*.xml";
            if (Dlg.ShowDialog() == DialogResult.OK)
            {
                StreamReader Infile = new StreamReader(Dlg.FileName);
                XmlSerializer Des = new XmlSerializer(typeof(List<StudentInfo>));
                Stu_Info = (List<StudentInfo>)Des.Deserialize(Infile);
                Infile.Close();
                dataGridView1.DataSource = Stu_Info;
            }
        }

        private void passedToolStripMenuItem_Click(object sender, EventArgs e)
        {
            var R = from Item in Stu_Info
                    where Item.total >= 50
                    select Item;
            dataGridView1.DataSource = R.ToArray();
            foreach (StudentInfo item in R)
            {
                pass.Enqueue(item);
            }
        }

        private void failedToolStripMenuItem_Click(object sender, EventArgs e)
        {
            var R = from Item in Stu_Info
                    where Item.total < 50
                    select Item;
            dataGridView1.DataSource = R.ToArray();
            foreach (StudentInfo item in R)
            {
                fail.Enqueue(item);
            }
        }

        private void excellentToolStripMenuItem_Click(object sender, EventArgs e)
        {
            var R = from Item in Stu_Info
                    where Item.total >= 84
                    select Item;
            dataGridView1.DataSource = R.ToArray();
            foreach (StudentInfo Item in R)
            {
                Excelent.Push(Item);
            }
        }

        private void veryGoodToolStripMenuItem_Click(object sender, EventArgs e)
        {
            var R = from Item in Stu_Info
                        where Item.total >=76 && Item.total <84
                        select Item;
                dataGridView1.DataSource = R.ToArray();
                foreach (StudentInfo Item in R)
                {
                    VeryGood.Push(Item);
                }
            }

        private void goodToolStripMenuItem_Click(object sender, EventArgs e)
        {
             var R = from Item in Stu_Info
                        where Item.total >= 68 && Item.total < 76
                        select Item;
                dataGridView1.DataSource = R.ToArray();
                foreach (StudentInfo Item in R)
                {
                    Good.Push(Item);
                }
        }

        private void countOfVeryGoodToolStripMenuItem_Click(object sender, EventArgs e)
        {
            MessageBox.Show(VeryGood.Count().ToString());
        }

        private void peekOfPeekToolStripMenuItem_Click(object sender, EventArgs e)
        {
            MessageBox.Show(Good.Peek().name);
        }

        private void removeItemFromFailedToolStripMenuItem_Click(object sender, EventArgs e)
        {
            MessageBox.Show(fail.Dequeue().name);
        }

        private void countOfPassedToolStripMenuItem_Click(object sender, EventArgs e)
        {
            MessageBox.Show(pass.Count().ToString());
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2();

        }
        }
    }

and in form2 contain textboxes to add new item for these list ! how use this !

Answer 1

A file is a collection of data stored in a disk with a specific name and a directory path. When a file is opened for reading or writing, it becomes a stream.

The stream is basically the sequence of bytes passing through the communication path. There are two main streams: the input stream and the output stream. The input stream is used for reading data from file (read operation) and the output stream is used for writing into the file (write operation).