private void PhoneTextBox_TextChanged(object sender, EventArgs e)
 {
     if (RegexValidation.IsPhoneValid(PhoneTextBox.Text))
     {
         nameErrorProvider.SetError(PhoneTextBox, String.Empty);
     }
     else
     {
         nameErrorProvider.SetError(PhoneTextBox, "Invalid phone number format.");
     }
 }
 private void AddressTextBox_TextChanged(object sender, EventArgs e)
 {
     if (RegexValidation.IsAddressValid(AddressTextBox.Text))
     {
         nameErrorProvider.SetError(AddressTextBox, String.Empty);
     }
     else
     {
         nameErrorProvider.SetError(AddressTextBox, "Invalid email format.");
     }
 }
 private void NameTextBox_TextChanged(object sender, EventArgs e)
 {
     if (RegexValidation.IsNameValid(NameTextBox.Text))
     {
         nameErrorProvider.SetError(NameTextBox, String.Empty);
     }
     else
     {
         nameErrorProvider.SetError(NameTextBox, "Invalid name format.");
     }
 }
        private void PhoneTextBox_Leave(object sender, EventArgs e)
        {
            string originalPhoneTextBoxText = PhoneTextBox.Text;

            PhoneTextBox.Text = RegexValidation.ReformatPhoneNumber(originalPhoneTextBoxText);
        }