Haow do I solve this I have tride variours ways pls help

<pre>namespace calci_2
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        Double rv = 0;
        string convoye = "";
        
        public MainWindow()
        {
            InitializeComponent();
        }

        private void but_7(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("7");
        }

        private void but_1(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("1");
        }

        private void button_2(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("2");
        }

        private void button_3(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("3");
        }

        private void button_4(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("4");
        }

        private void button_5(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("5");
        }

        private void button_6(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("6");
        }

        private void button_8(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("8");
        }

        private void button_9(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("9");
        }

        private void button_0(object sender, RoutedEventArgs e)
        {
            text_box__calculator.Text = text_box__calculator.Text + ("0");
        }

        private void operater_click(object sender, RoutedEventArgs e)
        {
            Button button = (Button)sender;

            convoye = button.Text;
            rv = Double.Parse(text_box__calculator.Text);
        }
    }
}