C#

const int bit00 = 0x00; // 00000000
const int bit10 = 0x80; // 10000000
const int bit20 = 0xC0; // 11000000
const int bit30 = 0xE0; // 11100000
const int bit40 = 0xF0; // 11110000
const int bit50 = 0xF8; // 11111000
const int bit07 = 0x7F; // 01111111
const int bit06 = 0x3F; // 00111111
const int bit05 = 0x1F; // 00011111
const int bit04 = 0x0F; // 00001111
const int bit03 = 0x07; // 00000111

public static int ReadUTF8Char(Stream s)
{
    int c = s.ReadByte();
    if (c == -1)
    {
        return -1;
    }
    else if ((c & bit10) == bit00)
    {
        return c;
    }
    else if ((c & bit30) == bit20)
    {
        var c2 = s.ReadByte();
        return c & bit05 << 6 | c2 & bit06;
    }
    else if ((c & bit40) == bit30)
    {
        var c2 = s.ReadByte();
        var c3 = s.ReadByte();
        return c & bit04 << 12 | c2 & bit06 << 6 | c3 & bit06;
    }
    else if ((c & bit50) == bit40)
    {
        var c2 = s.ReadByte();
        var c3 = s.ReadByte();
        var c4 = s.ReadByte();
        return c & bit03 << 18 | c2 & bit06 << 12 | c3 & bit06 << 6 | c2 & bit06;
    }
    else
    {
        // what is that?
        return c;
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using Microsoft.Win32;
using iTextSharp.text;
using iTextSharp.text.pdf;
using System.IO;
using System.Text.RegularExpressions;

namespace CV_maker
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        //============================================================
        //GUI Handling, cheking that user has entered valid information
        //============================================================

        private bool ErrorCheck(bool errorState)

        //Check if txboxName, txtboxBday, txtboxAddres, txtboxPhone, txtboxEmail are empty
 
        {
            bool isError;

            if(txtboxName.Text.Trim().Length == 0)
            { MessageBox.Show("Anna nimesi!", "Seis!", MessageBoxButton.OK, MessageBoxImage.Error);
            isError = true;
            }

            if (txtboxBday.Text.Trim().Length == 0)
            { MessageBox.Show("Anna Syntymäaikasi", "Seis!", MessageBoxButton.OK, MessageBoxImage.Error);
            isError = true;
            }

            if (txtboxPhone.Text.Trim().Length == 0)
            { MessageBox.Show("Anna Puhelinnumerosi!", "Seis!", MessageBoxButton.OK, MessageBoxImage.Error);
            isError = true;
            }

            if (txtboxAddress.Text.Trim().Length == 0)
            { MessageBox.Show("Anna Osoitteesi", "Seis!", MessageBoxButton.OK, MessageBoxImage.Error);
            isError = true;
            }

            if (txtboxEmail.Text.Trim().Length == 0)
            { MessageBox.Show("Anna S-postisi!", "Seis!", MessageBoxButton.OK, MessageBoxImage.Error);
            isError = true;
            }

            else 
            {
                isError = false;
            }
            return isError;
        }


        //============================================================
        //GUI Handling. Calling up methods
        //============================================================


        //Image Button
        private void btnAddimage_Click(object sender, RoutedEventArgs e)
        {
            addImage();
        }

        //To PDF Button
        private void btnSave_Click(object sender, RoutedEventArgs e)
        {
            bool ISOK;
            bool errorState;
            ISOK = ErrorCheck(errorState);
            if (ISOK == true)
            {
                MessageBox.Show("ERROR I WILL SHOW YOU THIS MESSAGE BEFORE REAL CODE");
            }

            //savepdf();
        }



        //============================================================
        //METHODS Called by GUI
        //===========================================================


        //ADD IMAGE BUTTON
        void addImage()
        {
            OpenFileDialog op = new OpenFileDialog();
            op.Title = "Select a picture";
            op.Filter = "All supported graphics|*.jpg;*.jpeg;*.png|" +
              "JPEG (*.jpg;*.jpeg)|*.jpg;*.jpeg|" +
              "Portable Network Graphic (*.png)|*.png";
            if (op.ShowDialog() == true)
            {
                PictureOmakuva.Source = new BitmapImage(new Uri(op.FileName));
            }
            return;
        }

        //Save PDF BUTTON
        void savepdf()

        {
            
                //VARIABLE DECLARATIONS

                string OwnName;

                //PULLING INFORMATION

                OwnName = txtboxName.Text;

                //SAVING THE PDF FILE
                FileStream fs = new FileStream(OwnName + " Curriculum Vitae.pdf", FileMode.Create, FileAccess.Write, FileShare.None);
                Document doc = new Document();
                PdfWriter writer = PdfWriter.GetInstance(doc, fs);
                doc.Open();
                doc.Add(new iTextSharp.text.Paragraph("Tämä on testi"));
                doc.Close();
            
        }


    }
}