With Xaml

xamlbuilder.rb

require 'rubygems'
require 'builder'
require 'PresentationCore'
require 'PresentationFramework'
require 'System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeytoken=b77a5c561934e089'
include System::Windows
StringReader = System::IO::StringReader;
XamlReader   = System::Windows::Markup::XamlReader
XmlReader    = System::Xml::XmlReader;

class System::Windows::Window
  def [](arg)
    self.find_name(arg.to_s)
  end
end
class Xaml
  def self.add_xaml_ns(hash)
    if not hash.key? "xmlns:x"
      hash["xmlns:x"] = "http://schemas.microsoft.com/winfx/2006/xaml"
    end
  end
  def self.add_presentation_ns(hash)
    if not hash.key? :xmlns
      hash[:xmlns] = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    end
  end
  def self.create(hash, &block)
    add_presentation_ns hash
    add_xaml_ns hash
    xaml = Builder::XmlMarkup.new(:indent => 2)
    yield(xaml)
    XamlReader.load(XmlReader.create(StringReader.new(xaml.target!.to_clr_string)))
  end
  def self.window(hash, &block)
    create(hash) do |xaml|
      xaml.Window(hash, &block)
    end
  end
end

window = Xaml.window( :Title => "Lef' Frontal Lobe",
                   :Width => 450, :SizeToContent => :Height) do |w|
   w.StackPanel :Margin => 15 do |layout|
     layout.StackPanel(:Orientation => :Horizontal) do |search_control|
       search_control.TextBox(:Width => 390, "x:Name" => "SearchBox" )
       search_control.Button(:Content => "Go", "x:Name" => "SearchButton")
     end
     layout.Label(:FontSize => 24, :Content => "Results",
                  :HorizontalAlignment => "Center", :Margin => 5 )
     layout.ListBox("x:Name" => "ResultsList")
   end
end

window[:SearchButton].click do |sender, args|
  items = window[:ResultsList].items
  items.clear
  items.add window[:SearchBox].text
end
Application.new().run(window)