private void btnRegister_Click(object sender, RoutedEventArgs e) { if (textBoxEmail.Text.Length == 0) { //errormessage.Text = "Enter an email."; textBoxEmail.Focus(); } else if (!Regex.IsMatch(textBoxEmail.Text, @"^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$")) { errormessage.Text = "Enter a valid email."; textBoxEmail.Select(0, textBoxEmail.Text.Length); textBoxEmail.Focus(); } else { string name = textBoxName.Text; string email = textBoxEmail.Text; string password = passwordBox1.Password; if (passwordBox1.Password.Length == 0) { errormessage.Text = "Enter password."; passwordBox1.Focus(); } else if (passwordBoxConfirm.Password.Length == 0) { errormessage.Text = "Enter Confirm password."; passwordBoxConfirm.Focus(); } else if (passwordBox1.Password != passwordBoxConfirm.Password) { errormessage.Text = "Confirm password must be same as password."; passwordBoxConfirm.Focus(); } else { errormessage.Text = ""; DB_Connect db_connect = new DB_Connect(); bool result = db_connect.InsertNewUser(name, password, email); if (result == true) { errormessage.Text = "Login succssfuly."; // here we will want to save the user email and nickname in app.config/ settings . Properties.Settings.Default["user_name"] = name; Properties.Settings.Default["user_email"] = email; Properties.Settings.Default.Save(); Reset(); this.Close(); } else { errormessage.Text = "Email alredy exists."; } } } }