Cara membuat kode SMS di Windows Phone

Kode mainpage.xaml: 

<phone:PhoneApplicationPage
    x:Class="Windows_SMS_Application.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">

    <!--LayoutRoot is the root grid where all page content is placed-->
    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <!--TitlePanel contains the name of the application and page title-->
        <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
            <TextBlock x:Name="ApplicationTitle" Text="Vijay's SMS Application" Style={StaticResource PhoneTextNormalStyle}"/>
            <TextBlock x:Name="PageTitle" Text="Windows 7 Phone" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
        </StackPanel>

        <!--ContentPanel - place additional content here-->
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <TextBlock Height="30" HorizontalAlignment="Left" FontSize="22" Margin="106,24,0,0" Name="textBlock1" Text="Please Enter Number" FontFamily="Verdana" VerticalAlignment="Top" Width="245" />
            <TextBox Height="72" HorizontalAlignment="Left" Margin="87,73,0,0" x:Name="textBox1" VerticalAlignment="Top"  Width="287" FontFamily="Verdana" FontSize="22"/>
            <TextBlock Height="30" HorizontalAlignment="Left" Margin="106,183,0,0" Name="textBlock2" Text="Please Enter Message" VerticalAlignment="Top" Width="240" FontFamily="Verdana" FontSize="22"/>
            <TextBox Height="153" HorizontalAlignment="Left" Margin="87,219,0,0" Name="textBox2" FontFamily="Verdana" FontSize="22" VerticalAlignment="Top" Width="287" />
            <Button Content="Send" Height="72" FontFamily="Verdana" FontSize="22" x:Name="button1" HorizontalAlignment="Left" Margin="157,418,0,0"  VerticalAlignment="Top" Width="160" Click="button1_Click" />
            <TextBlock Height="30" FontFamily="Verdana" FontSize="22" HorizontalAlignment="Left" Margin="87,528,0,0" x:Name="textBlock3" VerticalAlignment="Top" Width="335" />
        </Grid>
    </Grid>

    <!--Sample code showing usage of ApplicationBar-->
    <!--<phone:PhoneApplicationPage.ApplicationBar>
        <shell:ApplicationBar IsVisible="True" IsMenuEnabled="True">
            <shell:ApplicationBarIconButton IconUri="/Images/appbar_button1.png" Text="Button 1"/>
            <shell:ApplicationBarIconButton IconUri="/Images/appbar_button2.png" Text="Button 2"/>
            <shell:ApplicationBar.MenuItems>
                <shell:ApplicationBarMenuItem Text="MenuItem 1"/>
                <shell:ApplicationBarMenuItem Text="MenuItem 2"/>
            </shell:ApplicationBar.MenuItems>
        </shell:ApplicationBar>
    </phone:PhoneApplicationPage.ApplicationBar>-->

</phone:PhoneApplicationPage>

Kode mainpage.xaml.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Tasks;
using Microsoft.Phone.Shell;

namespace Windows_SMS_Application
{
    public partial class MainPage : PhoneApplicationPage
    {
        // Constructor
        public MainPage()
        {
            InitializeComponent();

        }
        SmsComposeTask objSmsComposeTask = new SmsComposeTask();
        PhoneApplicationService objPhoneService = PhoneApplicationService.Current;

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            if (textBox1.Text == "" || textBox2.Text == "")
            {
                textBlock3.Text = "Message Sent Unsuccessful";
                textBlock3.Foreground = new SolidColorBrush(Colors.Red);
            }
            else
            {
                objSmsComposeTask.To = textBox1.Text;
                objSmsComposeTask.Body = textBox2.Text;
                objSmsComposeTask.Show();
            }

        }
        protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)
        {
            objPhoneService.State["numbertext"] = textBox1.Text;
            objPhoneService.State["messagetext"] = textBox2.Text;
            base.OnNavigatedFrom(e);
        }
        protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
        {
            object sample;
            if (objPhoneService.State.TryGetValue("numbertext", out sample))
                textBox1.Text = sample as string;
            if (objPhoneService.State.TryGetValue("messagetext", out sample))
                textBox2.Text = sample as string;
            base.OnNavigatedTo(e);
        }

    }
}

Ntar tampilannya kayak gini: