I've create a solution, mixed the information of varius post.
Its a form, that contains a label and one textbox. The console output is redirected to the textbox.
There are too a class called ConsoleView that implements three publics methods: Show(), Close(), and Release(). The last one is for leave open the console and activate the Close button for view results.
The forms is called FrmConsole. Here are the XAML and the c# code.
The use is very simple:
ConsoleView.Show("Title of the Console");
For open the console. Use:
System.Console.WriteLine("The debug message");
For output text to the console.
Use:
ConsoleView.Close();
For Close the console.
ConsoleView.Release();
Leaves open the console and enables the Close button
XAML
<Window x:Class="CustomControls.FrmConsole"
    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"
    xmlns:local="clr-namespace:CustomControls"
    mc:Ignorable="d"
    Height="500" Width="600" WindowStyle="None" ResizeMode="NoResize" WindowStartupLocation="CenterScreen" Topmost="True" Icon="Images/icoConsole.png">
<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="40"/>
        <RowDefinition Height="*"/>
        <RowDefinition Height="40"/>
    </Grid.RowDefinitions>
    <Label Grid.Row="0" Name="lblTitulo" HorizontalAlignment="Center" HorizontalContentAlignment="Center" VerticalAlignment="Center" VerticalContentAlignment="Center" FontFamily="Arial" FontSize="14" FontWeight="Bold" Content="Titulo"/>
    <Grid Grid.Row="1">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="10"/>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="10"/>
        </Grid.ColumnDefinitions>
        <TextBox Grid.Column="1" Name="txtInner" FontFamily="Arial" FontSize="10" ScrollViewer.CanContentScroll="True" VerticalScrollBarVisibility="Visible" HorizontalScrollBarVisibility="Visible" TextWrapping="Wrap"/>
    </Grid>
    <Button Name="btnCerrar" Grid.Row="2" Content="Cerrar" Width="100" Height="30" HorizontalAlignment="Center" HorizontalContentAlignment="Center" VerticalAlignment="Center" VerticalContentAlignment="Center"/>
</Grid>
The code of the Window:
partial class FrmConsole : Window
{
    private class ControlWriter : TextWriter
    {
        private TextBox textbox;
        public ControlWriter(TextBox textbox)
        {
            this.textbox = textbox;
        }
        public override void WriteLine(char value)
        {
            textbox.Dispatcher.Invoke(new Action(() =>
            {
                textbox.AppendText(value.ToString());
                textbox.AppendText(Environment.NewLine);
                textbox.ScrollToEnd();
            }));
        }
        public override void WriteLine(string value)
        {
            textbox.Dispatcher.Invoke(new Action(() =>
            {
                textbox.AppendText(value);
                textbox.AppendText(Environment.NewLine);
                textbox.ScrollToEnd();
            }));
        }
        public override void Write(char value)
        {
            textbox.Dispatcher.Invoke(new Action(() =>
            {
                textbox.AppendText(value.ToString());
                textbox.ScrollToEnd();
            }));
        }
        public override void Write(string value)
        {
            textbox.Dispatcher.Invoke(new Action(() =>
            {
                textbox.AppendText(value);
                textbox.ScrollToEnd();
            }));
        }
        public override Encoding Encoding
        {
            get { return Encoding.UTF8; }
        }
    }
    //DEFINICIONES DE LA CLASE
    #region DEFINICIONES DE LA CLASE
    #endregion
    //CONSTRUCTORES DE LA CLASE
    #region CONSTRUCTORES DE LA CLASE
    public FrmConsole(string titulo)
    {
        InitializeComponent();
        lblTitulo.Content = titulo;
        Clear();
        btnCerrar.Click += new RoutedEventHandler(BtnCerrar_Click);
        Console.SetOut(new ControlWriter(txtInner));
        DesactivarCerrar();
    }
    #endregion
    //PROPIEDADES
    #region PROPIEDADES
    #endregion
    //DELEGADOS
    #region DELEGADOS
    private void BtnCerrar_Click(object sender, RoutedEventArgs e)
    {
        Close();
    }
    #endregion
    //METODOS Y FUNCIONES
    #region METODOS Y FUNCIONES
    public void ActivarCerrar()
    {
        btnCerrar.IsEnabled = true;
    }
    public void Clear()
    {
        txtInner.Clear();
    }
    public void DesactivarCerrar()
    {
        btnCerrar.IsEnabled = false;
    }
    #endregion  
}
the code of ConsoleView class
static public class ConsoleView
{
    //DEFINICIONES DE LA CLASE
    #region DEFINICIONES DE LA CLASE
    static FrmConsole console;
    static Thread StatusThread;
    static bool isActive = false;
    #endregion
    //CONSTRUCTORES DE LA CLASE
    #region CONSTRUCTORES DE LA CLASE
    #endregion
    //PROPIEDADES
    #region PROPIEDADES
    #endregion
    //DELEGADOS
    #region DELEGADOS
    #endregion
    //METODOS Y FUNCIONES
    #region METODOS Y FUNCIONES
    public static void Show(string label)
    {
        if (isActive)
        {
            return;
        }
        isActive = true;
        //create the thread with its ThreadStart method
        StatusThread = new Thread(() =>
        {
            try
            {
                console = new FrmConsole(label);
                console.ShowDialog();
                //this call is needed so the thread remains open until the dispatcher is closed
                Dispatcher.Run();
            }
            catch (Exception)
            {
            }
        });
        //run the thread in STA mode to make it work correctly
        StatusThread.SetApartmentState(ApartmentState.STA);
        StatusThread.Priority = ThreadPriority.Normal;
        StatusThread.Start();
    }
    public static void Close()
    {
        isActive = false;
        if (console != null)
        {
            //need to use the dispatcher to call the Close method, because the window is created in another thread, and this method is called by the main thread
            console.Dispatcher.InvokeShutdown();
            console = null;
            StatusThread = null;
        }
        console = null;
    }
    public static void Release()
    {
        isActive = false;
        if (console != null)
        {
            console.Dispatcher.Invoke(console.ActivarCerrar);
        }
    }
    #endregion
}
I hope this result usefull.