Möchte ein Formular erstellen, der mir HTML Code erzeugt. Benötige Ratschläge

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

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

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void buttonHtmlErstellen_Click(object sender, EventArgs e)
        {
            String zeile1;
            String zeile2;
            String zeile3;
            String zeile4;
            String zeile5;
            String zeile6;
            String zeilenFotos;
            decimal bildVon;
            decimal bildBis;

            zeile1 = "<div style=\"text-align: center;\"><font size=\"6\">" + textBoxTitel.Text + "</font></div>" + Environment.NewLine;  
            zeile2 = "<div style=\"text-align: center;\"><font size=\"5\"><br></font></div>" + Environment.NewLine;  
            zeile3 = "<div style=\"text-align: center;\"><font size=\"5\"><b><u>Infos:</u></b></font></div>" + Environment.NewLine;  
            zeile4 = "<div style=\"text-align: center;\"><font size=\"5\">" + textBoxInfo1.Text + "</font></div>" + Environment.NewLine;  
            zeile5 = "<div style=\"text-align: center;\"><font size=\"5\">" + textBoxInfo2.Text + "</font></div>" + Environment.NewLine;  
            zeile6 = "<div style=\"text-align: center;\"><font size=\"5\">Allgemeinzustand siehe Fotos<br></font></div><div><br></div>" + Environment.NewLine;  

            zeilenFotos = null;
            bildVon = numericUpDownVon.Value;
            bildBis = numericUpDownBis.Value;

            while (bildVon <= bildBis)
            {
                zeilenFotos = zeilenFotos + "<div style=\"text-align: center;\"><img src=\"http://MeineNAS/" + bildVon + ".jpg\" border=\"0\" alt=\"" + textBoxTitel.Text + "\"></div><div><br></div>" + Environment.NewLine;  
                bildVon++;
            }

            textBoxHtmlCode.Text = zeile1 + zeile2 + zeile3 + zeile4 + zeile5 + zeile6 + zeilenFotos;
        }

        private void buttonZwischenablage_Click(object sender, EventArgs e)
        {
            Clipboard.SetText(textBoxHtmlCode.Text);
        }

        private void buttonLeeren_Click(object sender, EventArgs e)
        {
            textBoxTitel.Clear();
            textBoxInfo1.Clear();
            textBoxInfo2.Clear();
            textBoxInfo3.Clear();
            numericUpDownVon.Value = 0;
            numericUpDownBis.Value = 0;
            textBoxHtmlCode.Clear();
        }

        private void textBoxTitel_Enter(object sender, EventArgs e)
        {
            textBoxTitel.SelectAll();
        }

        private void textBoxInfo1_Enter(object sender, EventArgs e)
        {
            textBoxInfo1.SelectAll();
        }

        private void textBoxInfo2_Enter(object sender, EventArgs e)
        {
            textBoxInfo2.SelectAll();
        }

        private void textBoxInfo3_Enter(object sender, EventArgs e)
        {
            textBoxInfo3.SelectAll();
        }

        private void numericUpDownVon_Enter(object sender, EventArgs e)
        {
            numericUpDownVon.Select(0, numericUpDownVon.Text.Length);
        }

        private void numericUpDownBis_Enter(object sender, EventArgs e)
        {
            numericUpDownBis.Select(0, numericUpDownBis.Text.Length);
        }
    }
}