• The .NET Framework includes lots of classes that are useful for providing an application driven by a GUI.
• The System.Windows.Forms namespace includes the following classes:

  Form
  Button
  TextBox
  Label
  MainMenu
  MenuItem
  

• If you are using Visual Studio.NET (an IDE from Microsoft), it has a wizard that allows you easily to produce a Windows Forms application.
• This wizard is not available if you are using Visual Studio.NET to produce C++ programs.
• The code that Visual Studio.NET's wizard generates is more verbose, but most of it is reasonably easy to understand.

using System;
using System.Drawing;
using System.Windows.Forms;
namespace MyWindowsConvert
{
    public class Form1 : Form
    {
        private TextBox textBox1;
        private Button button1;
        private Label label1;
        public Form1()
        {
            textBox1 = new TextBox();
            textBox1.Location = new Point(64, 32);
            textBox1.Size = new Size(120, 20);
            Controls.Add(textBox1);
            button1 = new Button();
            button1.Location = new Point(64, 64);
            button1.Size = new Size(120, 20);
            button1.Text = "Get Fahrenheit";
            button1.Click += new EventHandler(button1_Click);
            Controls.Add(button1);
            label1 = new Label();
            label1.Location = new Point(64, 104);
            label1.Size = new Size(120, 20);
            Controls.Add(label1);
            Text = "MyWindowsConvert";
        }
        private void button1_Click(object sender, EventArgs e)
        {
            double tCentigrade = double.Parse(textBox1.Text);
            double tFahrenheit = 32 + tCentigrade*9/5;
            label1.Text = tFahrenheit.ToString();
        }
        public static void Main() 
        {
            Form1 tForm1 = new Form1();
            Application.Run(tForm1);
        }
    }
}