How do I get WYSIWYG design in Blend/VS without merged ResourceDictionary in every XAML file?

Question

I've just removed a big memory issue for me, I used to merge our "Themes" resource dictionary in every xaml file instead of just in the app.cs.xaml.

However, after removing the merging in every file except the App.cs.xaml I've lost the design time styles/templates.

Please note: This only applies to the styles merged into our Themes.xaml (e.g. Color.xaml, Brushes.xaml - we have one for each type of style). Stuff defined directly in Themes.xaml (which we have none of..) works.

I see two solutions,

1) Have the merging commented out in XAML and just un-comment it when I want to work with the designs.

2) Have this in the default ctor of every control: (perhaps only works in Blend)

#if DEBUG
Resources.MergedDictionaries.Add(
                new ResourceDictionary()
                {
                    Source = new System.Uri(@"RD.xml")
                }
                );
#endif

There has to be a better way to get design time editing of pages and controls, anyone know?

Thank you!

Answer 1

Another way of doing it (the way we're going for now): Have a pre-build script comment out the merging in all XAML files.

Makes it harder to debug memory issues etc in DEBUG mode, but can be fully automated and fixes the issues for the final release.

Answer 2

The script idea doesn't seem like a good idea to me. You'd have so many "fake" revisions in your source control and my guess is that you'd have to spend a lot of time tweaking it.

I've been hoping that VS2010 and Expression Blend 3 will make big improvements in this area. Anyone try out the betas and know?

Answer 3

You can add resource distionary in Resources of App.xaml, that works perfectly for me. Or may be i m not getting u.

Answer 4

I've just removed a big memory issue for me, I used to merge our "Themes" resource dictionary in every xaml file instead of just in the app.cs.xaml.

Sorry for the offtopic, but could you provide any proof-link to authoritative source which describes those issues? It's not like I consider you as non-authoritative... just want to know a little bit more about this issue since I'm using almost the same technique for merging dictionaries.

Thanks.

Answer 5

What I do is add a class that inherits from ResourceDictionary and override the source property to check if IsInDesignMode is true.

If it is I set the source otherwise I leave the source blank (which effectivley prevents the dictionary from being merged at runtime)

public class BlendMergedDictionary : ResourceDictionary
{
 public bool IsInDesignMode
 {
  get
  {
   return (bool)DependencyPropertyDescriptor.FromProperty(
       DesignerProperties.IsInDesignModeProperty,
       typeof(DependencyObject)
       ).Metadata.DefaultValue;
  }
 }

 public new Uri Source
 {
  get { return base.Source; }
  set
  {
   if (!IsInDesignMode)
    return;

   Debug.WriteLine("Setting Source = " + value);
   base.Source = value;
  }
 }
}

Now when I need to reference the dictionary in Blend I merge in the dictionary like this

<ResourceDictionary.MergedDictionaries>
            <BlendHelpers:BlendMergedDictionary Source="Foo.xaml" />
</ResourceDictionary.MergedDictionaries>

You still have to "merge" in the dictionary in every file, but you don't pay the penalty of actually loading the dictionary at runtime. The merge is only there to support design time behavior.