MainWindow1.cs

// create a ScriptRuntime, the portal to the DLR Hosting API
// CreateFromConfiguration gets information, like languages
// are available, from an app.config configuration file
var runtime = ScriptRuntime.CreateFromConfiguration();

// create a ScriptEngine for IronRuby
var engine = runtime.GetEngine("IronRuby");

// a ScriptScope stores state between executions
var scope = engine.CreateScope();

// expose the current instance as "window" to the scripts
scope.SetVariable("window", this);

// execute a script against the scope, which modifies 
// that "window" variable set previously.
engine.Execute("window.Message.Text = 'Hello from Ruby!'", scope);