public class HandleTheme
{
    // light
    public static string GetLightUrl(DependencyObject obj)
    {
        return (string)obj.GetValue(LightUrlProperty);
    }
    public static void SetLightUrl(DependencyObject obj, string value)
    {
        obj.SetValue(LightUrlProperty, value);

Windows Registry Editor Version 5.00
 
[HKEY_CURRENT_USER\Software\Microsoft\Microsoft SQL Server\100\Tools\Shell\FontAndColors\{A27B4E24-A735-4D1D-B8E7-9716E1E3D8E0}]
"Colorable item format version"=dword:00000008
"Plain Text Foreground"=dword:00e0e0e0
"Plain Text Background"=dword:00303030
"Plain Text FontFlags"=dword:00000000
"Selected Text Foreground"=dword:00000000
"Selected Text Background"=dword:00c0c0c0
"Selected Text FontFlags"=dword:00000000

/// <summary>
/// Returns an application Url that's Theme relative.
/// images/users.gif
/// returns: /myapp/app_themes/{activetheme}/images/users.gif
/// </summary>
public static string ResolveThemeUrl(string themeRelativePath)
{
    string theme = null;
    
    // try to pick up active theme