Loading XAML at run time is really simple. I wrote a small sample to load the XAML at run time and than attach the event handler with the XAML object. I created following XAML page and copied it to the debug folder.

<Page
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Page1">
    <Grid>
        <Button Margin="0,0,9,38" Name="button1" Height="82" HorizontalAlignment="Right" VerticalAlignment="Bottom" Width="132">Button</Button>
    </Grid>
</Page>

and here is the C# code

 public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            LoadXAMLMethod();
        }

        Button ButtoninXAML;
        public void LoadXAMLMethod()
        {
            try
            {
                StreamReader mysr = new StreamReader("Page1.xaml");
                DependencyObject rootObject = XamlReader.Load(mysr.BaseStream) as DependencyObject;
                ButtoninXAML = LogicalTreeHelper.FindLogicalNode(rootObject, "button1") as Button ;
                ButtoninXAML.Click += new RoutedEventHandler(Button_Click);
                this.Content = rootObject;
            }
            catch (FileNotFoundException ex)
            {
                MessageBox.Show(ex.Message.ToString());   
            }
        }
        public void Button_Click(object sender, RoutedEventArgs e)
        {
            MessageBox.Show("Hi WPF"); 
        }
    }
}

do not forget to add following namespaces.

using System.IO;
using System.Windows.Markup;