//For signing into an account private void Button_SignIn(object sender, RoutedEventArgs e) { if (!(String.IsNullOrEmpty(userNameTxt.Text) || String.IsNullOrEmpty(passwordtxt.Password))) { bool userexists = ddb.CheckUsernameExists(userNameTxt.Text); if (userexists == true) { string username = ddb.GetUsername(userNameTxt.Text); string password = ddb.GetPassword(userNameTxt.Text); if (username == userNameTxt.Text && passwordtxt.Password == password) { BookShelf bookShelf = new BookShelf(userNameTxt.Text); bookShelf.Show(); bookShelf.Owner = this; this.Hide(); userNameTxt.Text = ""; passwordtxt.Password = ""; } else { MessageBox.Show("Check your Credentials", "Error !!!!"); } } } else { MessageBox.Show("Fill in your credentials", "Error !!!!"); } }