Debug helpers

ConsoleForm.cs

    public class FormConsole : IDisposable
    {
        private readonly Form _form;

        public FormConsole()
        {
            _form = new Form();
            var textBox = new RichTextBox {Name = "DebugFormTextBox"};

            _form.Controls.Add(textBox);
            textBox.Dock = DockStyle.Fill;
            _form.Show();
        }

        public void Dispose()
        {
            _form?.Dispose();
        }

        public Form GetForm()
        {
            return _form;
        }

        public void WriteLine(string line, params object[] args)
        {
            var box = _form.Controls["DebugFormTextBox"] as RichTextBox;
            box?.AppendMessage(line, box.ForeColor, args);
        }

        public void WriteLine(string line, Color color)
        {
            var box = _form.Controls["DebugFormTextBox"] as RichTextBox;
            box?.AppendMessage(line, color);
        }
    }

MessageBoxEx.cs

 public static class MessageBoxEx
    {
        public static void ShowException(Exception exception, string caption)
        {
            ShowError(exception.Message, caption);
        }

        public static void ShowInfo(string info)
        {
            ShowInfo(info, "Information");
        }

        public static void ShowInfo(string info, string caption)
        {
            MessageBox.Show(info, caption, MessageBoxButtons.OK, MessageBoxIcon.Information);
        }

        public static void ShowError(string error)
        {
            ShowError(error, "Error");
        }

        public static void ShowError(string error, string caption)
        {
            MessageBox.Show(error, caption, MessageBoxButtons.OK, MessageBoxIcon.Error);
        }

        public static DialogResult Confirm(string question)
        {
            return MessageBox.Show(question, @"Confirm",
                MessageBoxButtons.YesNo, MessageBoxIcon.Question,
                MessageBoxDefaultButton.Button2);
        }
    }

RichTextBoxExtensions.cs

   /// <summary>
    ///     A class providing extension methods for Windows Forms rich text box objects.
    /// </summary>
    public static class RichTextBoxExtensions
    {
        /// <summary>
        ///     Appends the message and ends with a new line (invoking if required) to the rich text box.
        /// </summary>
        /// <param name="box">The box to append the message to.</param>
        /// <param name="text">The text to append.</param>
        /// <param name="color">The color of the text to be appended.</param>
        /// <param name="args">The arguments, if any for string format..</param>
        public static void AppendMessage(this RichTextBox box, string text, Color color, params object[] args)
        {
            if (box.InvokeRequired)
                box.InvokeAppendLine(text, color, args);
            else
                box.AppendLine(text, color, args);
        }

        /// <summary>
        ///     Appends the message (and does not end with a new line) invoking if required to the rich text box.
        /// </summary>
        /// <param name="box">The box to append the message to.</param>
        /// <param name="text">The text to append.</param>
        /// <param name="color">The color of the text to be appended.</param>
        /// <param name="args">The arguments, if any for string format..</param>
        public static void AppendTextEx(this RichTextBox box, string text, Color color, params object[] args)
        {
            if (box.InvokeRequired)
                box.InvokeAppendText(text, color, args);
            else
                box.AppendText(text, color, args);
        }

        private static void AppendText(this RichTextBox box, string text, Color color, params object[] args)
        {
            text = string.Format(text, args);
            if (color == Color.Empty)
            {
                box.AppendText(text);
                return;
            }

            box.SelectionStart = box.TextLength;
            box.SelectionLength = 0;

            box.SelectionColor = color;
            box.AppendText(text);
            box.SelectionColor = box.ForeColor;

            box.SelectionStart = box.TextLength;
            box.ScrollToCaret();
        }

        private static void AppendLine(this RichTextBox box, string text, Color color, params object[] args)
        {
            box.AppendText("\n" + text, color == Color.Empty ? box.ForeColor : color, args);
        }

        private static void InvokeAppendText(this RichTextBox box, string text, Color color, params object[] args)
        {
            box.Invoke((MethodInvoker)delegate { box.AppendText(text, color, args); });
        }

        private static void InvokeAppendLine(this RichTextBox box, string text, Color color, params object[] args)
        {
            box.Invoke((MethodInvoker)delegate { box.AppendLine(text, color, args); });
        }
    }