private void encrypt_button_Click(object sender, EventArgs e) { string text = unciphered_text_box.Text; for (int i = 0; i < text.Length; ++i) { if (not_allowed_symbol(text[i])) { MessageBox.Show("Input only number, syms of specified aphabet or spaces!"); return; } } text = letter_cryptor.encrypt(text); ciphered_text.Text = numeric_cryptor.encrypt(text); binary_ciphered_text.Text = get_binary_string(ciphered_text.Text); }