KeyPress ve Error Provider Kullanımı

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 KeyPress
{
    public partial class Form1 : Form
    {
        DateTime dogumTarih = new DateTime();
        string ad = "";
        string soyad = "";
        string tcNo = "";

        public Form1()
        {
            InitializeComponent();
        }

        private **** btnFormuAc_Click(object sender, EventArgs e)
        {
            formerrorprovider f = new formerrorprovider();
            f.BunuAcanform = this;
            f.Show();
            this.Hide();
        }

        private **** btnKaydet_Click(object sender, EventArgs e)
        {
            ad = txtAd.Text;
            soyad = txtSoyad.Text;
            dogumTarih = DateTime.Parse(txtDtarih.Text);
            tcNo = txtTCNO.Text;
        }

        private **** txtAd_KeyPress(object sender, KeyPressEventArgs e)
        {

            if (char.IsNumber(e.KeyChar) && e.KeyChar != '\b')
            {
                e.Handled = true;
            }
        }

        private **** txtSoyad_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (char.IsNumber(e.KeyChar) && e.KeyChar != '\b')
            {
                e.Handled = true;
            }
        }

        private **** txtDtarih_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (!char.IsNumber(e.KeyChar) && e.KeyChar != '.' && e.KeyChar != '\b')
                e.Handled = true;
        }

        private **** txtTCNO_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (!char.IsNumber(e.KeyChar) && e.KeyChar != '\b')
                e.Handled = true;
        }
    }
}
   






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 KeyPress
{
    public partial class formerrorprovider : Form
    {
        public formerrorprovider()
        {
            InitializeComponent();
        }

        public Form1 BunuAcanform = null;

        private **** txtkod_Validating(object sender, CancelEventArgs e)
        {
            if (string.IsNullOrEmpty(txtkod.Text) || txtkod.Text.Trim().Equals(""))
                return;
            if (!char.IsLetter(txtkod.Text[0]) || txtkod.Text.Length != 5)
            {
                errorProvider1.SetError(txtkod, "Firma kodu 5 karakterden oluşmalı ve ilk karakter harf olmalı");
                e.Cancel=true;
            }
            else
                errorProvider1.Clear();
        }

        private **** btnKaydetIlerle_Click(object sender, EventArgs e)
        {
            MessageBox.Show("Diger bölümü hazır olmadıgından ilerleyemeyeceksiniz...");
        }


        private **** frmerrorprovider_FormClosed(object sender, FormClosedEventArgs e)
        {
            BunuAcanform.Show();
        }
    }
}