Старый добрый шифровщик

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 WindowsFormsApplication24
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
 
private bool IsKeyValid(string key)
{
foreach (char c in key)
if (!Char.IsDigit(c)) 
return false;
return true;
}
 
private bool IsCapitalRussianLetter(char c)
{
return (c >= 'А') && (c <= 'Я');
}
 
private bool IsSmallRussianLetter(char c)
{
return (c >= 'а') && (c <= 'я');
}
 
private bool IsKeyValid(string key)
{
foreach (char c in key)
if ((c < '0') || (c > '9'))
return false;
return true;
}
 
 
private void button1_Click(object sender, EventArgs e)
{ 
string slovo; 
slovo = textBox1.Text;
string kodirovochka;
kodirovochka = textBox2.Text;
int r798 = System.Convert.ToInt32(kodirovochka); 
 
 
char[] alfavit = {'а','б','в','г','д','е','ё','ж','з','и','й','к',
'л','м','н','о','п','р','с','т','у','ф','х','ц','ч ',
'ш','щ','ъ','ы','ь','э','ю','я','1','2','3','4','5 ','6','7','8','9','0'};
char[] slovooo = slovo.ToCharArray();
char[] rezult = new char[textBox1.Text.Length];
for (int i = 0; i < slovooo.Length; i++)
{
for (int j = 0; j < alfavit.Length; j++)
{
if (alfavit[j].Equals(slovooo[i]) == true)
{
rezult[i] = alfavit[j + r798];
 
}
 
}
 
}
string s = new string(rezult);
textBox3.Text = s;
 
}
 
 
 
}
}