enum TextBoxMode
{
    SingleLine,
    MultiLine
}

TextBox CreateTextBox(string label, TextBoxMode textBoxMode)
{
    var lbl = new Label();
    lbl.Content = $"{label}:";
    lbl.Dump();

    var textBox = new TextBox();
    if (textBoxMode == TextBoxMode.MultiLine)
    {
        textBox.AcceptsReturn = true;
        textBox.AcceptsTab = true;
        textBox.Height = 150;
        textBox.VerticalScrollBarVisibility = ScrollBarVisibility.Visible;
        textBox.HorizontalScrollBarVisibility = ScrollBarVisibility.Visible;
    }
    textBox.FontFamily = new System.Windows.Media.FontFamily("Courier New");
    textBox.Dump();

    return textBox;
}

Button CreateButton(string caption)
{
    var button = new Button();
    button.Content = caption;
    button.Width = 100;
    button.Margin = new System.Windows.Thickness(5);
    button.Dump();

    return button;
}

void Main()
{
    var textName = CreateTextBox("Name", TextBoxMode.SingleLine);
    var textInput = CreateTextBox("Input", TextBoxMode.MultiLine);
    var btnGo = CreateButton("Go");
    var textOutput = CreateTextBox("Output", TextBoxMode.MultiLine);

    btnGo.Click += (s, e) => textOutput.Text = Process(textInput.Text);
}

string Process(string input)
{
    return input;
}