Windows Forms: How to read and write to text file in C#

Step 1: Click New Project, then select Visual C# on the left, then Windows and then select Windows Forms Application. Name your project "TextFile" and then click OK

Step 2: Design your form as below

Step 3: Add code to button click event handler as below

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

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

        private async void btnRead_Click(object sender, EventArgs e)
        {
            //Read text file
            using(OpenFileDialog ofd = new OpenFileDialog() { Filter="Text Documents|*.txt", ValidateNames = true, Multiselect = false })
            {
                if (ofd.ShowDialog() == DialogResult.OK)
                {
                    using(StreamReader sr = new StreamReader(ofd.FileName))
                    {
                        txtText.Text = await sr.ReadToEndAsync();
                    }
                }
            }
        }

        private async void btnWrite_Click(object sender, EventArgs e)
        {
            //Write text file
            using(SaveFileDialog sfd = new SaveFileDialog() { Filter="Text Documents|*.txt", ValidateNames = true })
            {
                if (sfd.ShowDialog() == DialogResult.OK)
                {
                    using(StreamWriter sw = new StreamWriter(sfd.FileName))
                    {
                        await sw.WriteLineAsync(txtText.Text);
                        MessageBox.Show("You have been successfully saved.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                }
            }
        }
    }
}

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