QuestionAsker.xaml

<UserControl x:Class="IsAProgrammer.QuestionAsker"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignHeight="364" d:DesignWidth="470"
    DataContext="{Binding QuestionAskerViewModel}">

    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height=".2*" />
            <RowDefinition Height=".7*" />
            <RowDefinition Height=".1*" />
        </Grid.RowDefinitions>
        <TextBlock Grid.Row="0" Margin="5"  Text="{Binding CurrentQuestion.QuestionText}"/>
        <TextBox Grid.Row="1" Name="CodeBox" Text="{Binding CurrentQuestion.AnswerText}" Margin="5" TextWrapping="Wrap" AcceptsReturn="True" CaretBrush="Black" KeyDown="CodeBox_KeyDown" />
        
    </Grid>
</UserControl>

QuestionAsker.xaml.cs

using System;
using System.Windows.Controls;
using System.Windows.Input;
using IsAProgrammer.QuestionService;

namespace IsAProgrammer
{
    public partial class QuestionAsker : UserControl
    {
        public QuestionAskerVM QuestionAskerViewModel { get; set; }
        public QuestionAsker()
        {
            InitializeComponent();
            QuestionAskerViewModel = new QuestionAskerVM();
            DataContext = QuestionAskerViewModel;

        }



        private const string Tab = "    ";
        private void CodeBox_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Tab)
            {
                int selectionStart = CodeBox.SelectionStart;
                CodeBox.Text = String.Format("{0}{1}{2}",
                        CodeBox.Text.Substring(0, CodeBox.SelectionStart),
                        Tab,
                        CodeBox.Text.Substring(CodeBox.SelectionStart + CodeBox.SelectionLength, (CodeBox.Text.Length) - (CodeBox.SelectionStart + CodeBox.SelectionLength))
                        );
                e.Handled = true;
                CodeBox.SelectionStart = selectionStart + Tab.Length;
            }
        }
    }
}

QuestionAskerVM.cs

using System.Windows;
using IsAProgrammer.QuestionService;

namespace IsAProgrammer
{
    public class QuestionAskerVM: DependencyObject
    {
        

        public QuestionAskerVM()
        {
            QuestionServiceClient client = new QuestionServiceClient();
            client.GetQuestionCompleted += QuestionRecieved;
            client.GetQuestionAsync();
        }

        private void QuestionRecieved(object sender, GetQuestionCompletedEventArgs e)
        {
            CurrentQuestion = e.Result;
        }



        // This is the current question.
        public Question CurrentQuestion
        {
            get { return (Question)GetValue(CurrentQuestionProperty); }
            set { SetValue(CurrentQuestionProperty, value); }
        }
        public static readonly DependencyProperty CurrentQuestionProperty = DependencyProperty.Register("CurrentQuestion", typeof(Question), typeof(QuestionAskerVM), new PropertyMetadata(null));


        // This is the current answer.
        public Answer CurrentAnswer
        {
            get { return (Answer)GetValue(CurrentAnswerProperty); }
            set { SetValue(CurrentAnswerProperty, value); }
        }
        public static readonly DependencyProperty CurrentAnswerProperty = DependencyProperty.Register("CurrentAnswer", typeof(Answer), typeof(QuestionAskerVM), new PropertyMetadata(null));

        
    }
}