Instantiate ResourceDictionary xaml from other Assembly

Question

I have defined a Reource Dictionary in a WPF Class Library containing colors and brushes, called BrushResources.xaml.

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Lots of Colors and Brushes here>
</ResourceDictionary>

I want to use some of the Brushes in code from another assembly, which references this library project. How do get an Instance of ResourceDictionary of it?

Answer 1

What you're asking is a component of the functionality necessary to provide true skinning in an application. Getting resources from a separate assembly involves reading the compiled XAML, or BAML from the other assembly. Here is a method I use in a skinning library to retrieve the BAML from an assembly:

//Relevant Namespaces:
//using System.Windows.Baml2006;
//using System.Xaml;

public static List<Stream> GetBamlStreams(AssemblyName skinAssemblyName) 
{ 
    List<Stream> bamlStreams = new List<Stream>(); 
    Assembly skinAssembly = Assembly.Load(skinAssemblyName); 
    string[] resourceDictionaries = skinAssembly.GetManifestResourceNames(); 
    foreach (string resourceName in resourceDictionaries) 
    { 
        ManifestResourceInfo info = skinAssembly.GetManifestResourceInfo(resourceName); 
        if (info.ResourceLocation != ResourceLocation.ContainedInAnotherAssembly) 
        { 
            Stream resourceStream = skinAssembly.GetManifestResourceStream(resourceName); 
            using (ResourceReader reader = new ResourceReader(resourceStream)) 
            { 
                foreach (DictionaryEntry entry in reader) 
                { 
                    //TODO: Figure out if this is a ResourceDictionary I care about
                    //Key will be name of the RD (BrushResources.baml, in your case)
                    if (IsRelevantResource(entry)) 
                    { 
                         bamlStreams.Add(entry.Value as Stream); 
                    } 
                } 
            } 
        } 
    } 
    return bamlStreams; 
}

Then, to convert the BAML to specific resources, you do the following:

//If .NET 3.5, need this initialization:
//Type xamlType = typeof(System.Windows.Markup.XamlReader);
//LoadBamlMethod = xamlType.GetMethod(LOAD_BAML_METHOD, BindingFlags.NonPublic | BindingFlags.Static);

public static T LoadBaml<T>(Stream stream) 
{ 
    //For .net 3.5: 
    //ParserContext parserContext = new ParserContext(); 
    //object[] parameters = new object[] { stream, parserContext, null, false }; 
    //object bamlRoot = LoadBamlMethod.Invoke(null, parameters); 
    //return (T)bamlRoot; 

    //For .net 4.0
    var reader = new Baml2006Reader(stream); 
    var writer = new XamlObjectWriter(reader.SchemaContext); 
    while (reader.Read()) 
            writer.WriteNode(reader); 
    return (T)writer.Result; 
} 

And in order to merge the resources from the other assembly into the current assembly:

private void LoadResources() 
{ 
    List<Stream> bamlStreams = GetBamlStreams(FullName); 
    foreach (Stream stream in bamlStreams) 
    { 
        ResourceDictionary rd = LoadBaml<ResourceDictionary>(stream);
        Application.Current.Resources.MergedDictionaries.Add(rd)
    } 
} 

This example does the work in a very generic manner for skinning purposes, but you can streamline this to accomplish your specific goal if necessary. You can see a skinning library that uses this method here on github, with a few examples to demonstrate.