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Wpf HowTo: Add a Debug/Output Console to your Application

This example shows how to make a multi-threaded handler for the built in Console commands.

You can set Console.Out to any TextWriter. So you simply have to create your own TextWriter to handle cross-threaded handling of messages to your user interface.

Below is an example of a writing Console messages to a TextBox from two different threads.

 
TextBoxOutputter.cs

using System;
using System.IO;
using System.Text;
using System.Windows.Controls;
 
namespace WpfApplication68
{
    public class  TextBoxOutputter : TextWriter
    {
        TextBox textBox = null;
 
        public TextBoxOutputter(TextBox output)
        {
            textBox = output;
        }
 
        public override  void Write(char value)
        {
            base.Write(value);
            textBox.Dispatcher.BeginInvoke(new Action(() =>
            {
                textBox.AppendText(value.ToString());
            }));
        }
 
        public override  Encoding Encoding
        {
            get { return System.Text.Encoding.UTF8; }
        }
    }
}

Note: It's using the TextBox's Dispatcher to append the text. This prevents threading problems.

MainWindow.xaml

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Class="WpfApplication68.MainWindow"
        Title="MainWindow" Height="350" Width="525"
        xmlns:local="clr-namespace:WpfApplication68">
     
    <Grid>
        <TextBox Height="200" Width="400" x:Name="TestBox"/>
    </Grid>
 
</Window>

MainWindow.xaml.cs

using System;
using System.Windows;
using System.Threading;
 
namespace WpfApplication68
{
    public partial  class MainWindow : Window
    {
        TextBoxOutputter outputter;
 
        public MainWindow()
        {
            InitializeComponent();
 
            outputter = new  TextBoxOutputter(TestBox);
            Console.SetOut(outputter);
            Console.WriteLine("Started");
 
            var timer1 = new  Timer(TimerTick, "Timer1", 0, 1000);
            var timer2 = new  Timer(TimerTick, "Timer2", 0, 500);
        }
 
        void TimerTick(object state)
        {
            var who = state as  string;
            Console.WriteLine(who);
        }
 
    }
}

This small article is part of a series of WPF "How To" articles, in response to real user questions on the MSDN WPF Forum.