Form1.cs

Using C# class system.

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 Program9_1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Pet myPet = new Pet();
            getPetData(myPet);

            label4.Text = "Name: " + myPet.Name + "
" +
                          "Type: " + myPet.Type + "
" +
                          "Age: " + myPet.Age.ToString();
        }

        private void getPetData(Pet pet)
        {
            try
            {
                pet.Name = textBox1.Text;
                pet.Type = textBox2.Text;
                int age;
                if (int.TryParse(textBox3.Text, out age))
                {
                    pet.Age = age;
                }
                else
                {
                    MessageBox.Show("Invalid age.");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
    }
}

Pet.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Program9_1
{
    class Pet
    {
        private string _name, _type;
        private int _age;

        public Pet()
        {
            _name = "";
            _type = "";
            _age = 0;
        }

        public string Name
        {
            get
            {
                return _name;
            }
            set
            {
                _name = value;
            }
        }

        public string Type
        {
            get
            {
                return _type;
            }
            set
            {
                _type = value;
            }
        }

        public int Age
        {
            get
            {
                return _age;
            }
            set
            {
                _age = value;
            }
        }
    }
}