gombok

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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
          InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {

        }
        private void groupBox1_Enter(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
          /*label1.Text = "Címke";                   // 1. feladat
          button1.Text = "OKgomb";*/                 // 2. feladat
          //label1.Text = textBox1.Text;
          int a, b;
          a = Convert.ToInt32(textBox1.Text);
          b = Convert.ToInt32(textBox2.Text);
          label1.Text = Convert.ToString(a * b);
        }
        private void label1_Click(object sender, EventArgs e)
        {

        }
        static int bal, jobb;
        private void textBox1_TextChanged(object sender, EventArgs e)
        {
          if (textBox1.Text == "")
          {
            bal = 0;
          }
          else
          {
            bal = Convert.ToInt32(textBox1.Text);
          }
          label1.Text = Convert.ToString(bal * jobb);
        }
        private void textBox2_TextChanged(object sender, EventArgs e)
        {
          if (textBox2.Text == "")
          {
            jobb = 0;
          }
          else
          {
            jobb = Convert.ToInt32(textBox2.Text);
          }
          label1.Text = Convert.ToString(bal * jobb);
        }
    }
}